user-1: As a lay Buddhist, I know it is almost impossible for me to attain Enlightenment in this life. So if I keep enlightenment as a goal in mind it creates frustration, as I am not progressing in meditation and, life seems hopeless as Enlightenment is an impossible pursuit. However, if I don't think of enlightenment then I don't have any good motivation to do meditation and keep the precepts. 
How should I get out of in this confusion? Life as a Buddhist seems almost unpracticle. Any advise?

user111: Did you kill your mother or father?
If the answer is no, you cannot say for sure  that it is impossible for you to attain  enlightenment within this life.
So when you are meditating if this worry arises, simply remind yourself worrying... worrying... worrying... or doubting... doubting... doubting... until it goes away. Then get back to your meditation.

user471: The goal in Buddhism is the end of suffering. But why do you want to reach the end of suffering? The reason is to attain the only permanent happiness, which is Nibbana.
So, the mission in Buddhism is really the pursuit of happiness. The Buddha discovered that both over-indulgence and over-asceticism are not conducive to the path to the end of suffering. So, he prescribed the middle way through the Noble Eightfold Path.
If you follow the middle way, you can have long term, medium term and short term goals of happiness.
The long term goal associated with this mission is attaining Nibbana (permanent happiness). It might take multiple births, maybe even aeons to achieve this.
The medium term goal would be to try to achieve: at least stream entry for Theravada and strong cultivation of Bodhicitta for Mahayana. You can also get more info on stream entry in this YouTube video talk.
The short term goal would be to try to achieve and maintain happiness in this life and future lives (which includes avoiding unfortunate rebirths). At the very minimum, you need to keep the five precepts with heedfulness (appamada). Going a little further, you need to practise more of virtue (sila) with heedfulness (appamada).
This short term goal is described in the Ittha Sutta:

Long life, beauty, status, honor, heaven, high birth: To those who
  delight in aspiring for these things in great measure, continuously,
  the wise praise heedfulness in making merit.
The wise person, heedful, acquires a two-fold welfare: welfare in this
  life & welfare in the next. By breaking through to his welfare he's
  called prudent, wise.

For lay followers, there is plenty of advice on achieving the short to medium term goals in the Gihi Sutta (or Discourse to the Householder), Sigalovada Sutta, Dighajanu Sutta and Anana Sutta. The minimum training rules imposed on lay followers are the five precepts.
For those in a hurry to Nibbana, there are the more advanced training paths of anagarika (sort of a pre-monk or pre-nun), novice monk or nun, and fully ordained monk or nun. Please see this answer for details.

user13154: Don't focus on suffering as it is the reason for suffering. You can have a goal of reaching that eternal freedom. But, make sure you enjoy the journey without too focusing on the end...

-1: <p>As a lay Buddhist, I know it is almost impossible for me to attain Enlightenment in this life. So if I keep enlightenment as a goal in mind it creates frustration, as I am not progressing in meditation and, life seems hopeless as Enlightenment is an impossible pursuit. However, if I don't think of enlightenment then I don't have any good motivation to do meditation and keep the precepts. </p>

<p>How should I get out of in this confusion? Life as a Buddhist seems almost unpracticle. Any advise?</p>
 111: <p>Did you kill your mother or father?</p>

<p>If the answer is no, you cannot say for sure  that it is impossible for you to attain  enlightenment within this life.</p>

<p>So when you are meditating if this worry arises, simply remind yourself worrying... worrying... worrying... or doubting... doubting... doubting... until it goes away. Then get back to your meditation.</p>
 471: <p>The goal in Buddhism is the end of suffering. But why do you want to reach the end of suffering? The reason is to attain the only permanent happiness, which is Nibbana.</p>

<p>So, the mission in Buddhism is really the pursuit of happiness. The Buddha discovered that both over-indulgence and over-asceticism are not conducive to the path to the end of suffering. So, he prescribed the middle way through the <a href="https://www.accesstoinsight.org/lib/authors/bodhi/waytoend.html" rel="nofollow noreferrer">Noble Eightfold Path</a>.</p>

<p>If you follow the middle way, you can have long term, medium term and short term goals of happiness.</p>

<p>The long term goal associated with this mission is attaining Nibbana (permanent happiness). It might take multiple births, maybe even aeons to achieve this.</p>

<p>The medium term goal would be to try to achieve: at least <a href="https://www.accesstoinsight.org/lib/study/into_the_stream.html" rel="nofollow noreferrer">stream entry</a> for Theravada and strong cultivation of <a href="https://en.wikipedia.org/wiki/Bodhicitta" rel="nofollow noreferrer">Bodhicitta</a> for Mahayana. You can also get more info on stream entry in <a href="https://youtu.be/VI3dT4aXkfM" rel="nofollow noreferrer">this YouTube video talk</a>.</p>

<p>The short term goal would be to try to achieve and maintain happiness in this life and future lives (which includes avoiding unfortunate rebirths). At the very minimum, you need to keep <a href="http://www.accesstoinsight.org/ptf/dhamma/sila/pancasila.html" rel="nofollow noreferrer">the five precepts</a> with <a href="https://buddhism.stackexchange.com/q/22181/471">heedfulness (appamada)</a>. Going a little further, you need to practise more of <a href="https://www.accesstoinsight.org/ptf/dhamma/sila/index.html" rel="nofollow noreferrer">virtue (sila)</a> with <a href="https://buddhism.stackexchange.com/q/22181/471">heedfulness (appamada)</a>.</p>

<p>This short term goal is described in the <a href="http://www.accesstoinsight.org/tipitaka/an/an05/an05.043.than.html" rel="nofollow noreferrer">Ittha Sutta</a>:</p>

<blockquote>
  <p>Long life, beauty, status, honor, heaven, high birth: To those who
  delight in aspiring for these things in great measure, continuously,
  the wise praise <a href="https://buddhism.stackexchange.com/q/22181/471">heedfulness</a> in making merit.</p>
  
  <p>The wise person, <a href="https://buddhism.stackexchange.com/q/22181/471">heedful</a>, acquires a two-fold welfare: welfare in this
  life &amp; welfare in the next. By breaking through to his welfare he's
  called prudent, wise.</p>
</blockquote>

<p>For lay followers, there is plenty of advice on achieving the short to medium term goals in the <a href="http://www.accesstoinsight.org/tipitaka/an/an05/an05.179.than.html" rel="nofollow noreferrer">Gihi Sutta (or Discourse to the Householder)</a>, <a href="http://www.accesstoinsight.org/tipitaka/dn/dn.31.0.nara.html" rel="nofollow noreferrer">Sigalovada Sutta</a>, <a href="http://www.accesstoinsight.org/tipitaka/an/an08/an08.054.than.html" rel="nofollow noreferrer">Dighajanu Sutta</a> and <a href="http://www.accesstoinsight.org/tipitaka/an/an04/an04.062.than.html" rel="nofollow noreferrer">Anana Sutta</a>. The minimum training rules imposed on lay followers are <a href="http://www.accesstoinsight.org/ptf/dhamma/sila/pancasila.html" rel="nofollow noreferrer">the five precepts</a>.</p>

<p>For those in a hurry to Nibbana, there are the more advanced training paths of anagarika (sort of a pre-monk or pre-nun), novice monk or nun, and fully ordained monk or nun. Please see <a href="https://buddhism.stackexchange.com/a/11771/471">this answer</a> for details.</p>
 13154: <p>Don't focus on suffering as it is the reason for suffering. You can have a goal of reaching that eternal freedom. But, make sure you enjoy the journey without too focusing on the end...</p>
