What should I do about my friend who wants me to help her cheat? Friend: Rome

Rome and I started at our new school last year as juniors. We are both now seniors. At this school, we have a chance to graduate high school with our AA degrees. In fact, we are graduating with both our high school diplomas and our AA degrees in less than 3 months. I made the regrettable decision of skipping a few biology classes during my second semester at the college/high school. Rome kindly gave me the notes to which I was very thankful and ended up passing the class with a little bit of extra studying. Due to her helping me, I ended up helping her understand a few assignments for our senior CAPSTONE class (a graduation requirement). This class is a little difficult, so I myself even asked for a few ideas from friends for writing up my final presentation. However, Rome asked for me to send her my ENTIRE presentation slideshow so she can basically write hers up in the same way. Not exactly cheating since she's only copying my format and her topic is different than mine, but still frustrating that she didn't come up with some originality of her own. This semester me and her both have Psychology with the same teacher, just on different days. So her tests and assignments are always due the day after mine. She never can remember when the assignments are due, always asking me when mine is due. This is also incredibly frustrating as I have the care to memorize when my assignments are due. Recently she has been asking me for my homework assignments and take home tests for this class. She also has been asking me what will be on the in-class test. I made the unfortunate mistake of helping her the once by sending her the answers for 1 homework assignment and half of 1 of a take-home test. I do not plan on sending her any more answers or helping again, but she still sends emails asking for my calculator, for assignment dates, test answers, etc. I don't know what to do about her, and I don't want to risk her telling the professor that I have helped her cheat if I do not continue to help her.
Breaking down this wall of text....


  Rome and I started at our new school last year as juniors. We are both now seniors. At this school, we have a chance to graduate high school with our AA degrees. In fact, we are graduating with both our high school diplomas and our AA degrees in less than 3 months. I made the regrettable decision of skipping a few biology classes during my second semester at the college/high school. Rome kindly gave me the notes to which I was very thankful and ended up passing the class with a little bit of extra studying. Due to her helping me, I ended up helping her understand a few assignments for our senior CAPSTONE class (a graduation requirement). This class is a little difficult, so I myself even asked for a few ideas from friends for writing up my final presentation. 


So far so good, this is completely normal and acceptable behavior among classmates.


  However, Rome asked for me to send her my ENTIRE presentation slideshow so she can basically write hers up in the same way. Not exactly cheating since she's only copying my format and her topic is different than mine, but still frustrating that she didn't come up with some originality of her own. 


Still mostly okay; if you are working on separate topics, hard to see how this could be considered cheating.


  This semester me and her both have Psychology with the same teacher, just on different days. So her tests and assignments are always due the day after mine. She never can remember when the assignments are due, always asking me when mine is due. This is also incredibly frustrating as I have the care to memorize when my assignments are due. 


This seems like a very minor, irrelevant point. Either help her or tell her to go away, calling it "incredibly frustrating" seems unnecessarily dramatic. But everything up to this point is really irrelevant. 


  Recently she has been asking me for my homework assignments and take home tests for this class. She also has been asking me what will be on the in-class test. I made the unfortunate mistake of helping her the once by sending her the answers for 1 homework assignment and half of 1 of a take-home test. 


Here's the problem! She asked you to cheat and you said okay. That makes both of you cheaters. Period. 


  I do not plan on sending her any more answers or helping again


Good.


  but she still sends emails asking for my calculator, for assignment dates, test answers, etc. I don't know what to do about her, and I don't want to risk her telling the professor that I have helped her cheat if I do not continue to help her.


Yes, this is the risk you take when you do illegal, unethical things. 


The part about the calculator and assignment date is fine; that's just an annoyance that you'll have to address, try asking on interpersonal.SE if necessary
But you need to be sure that you never give her test answers or participate in any other form of cheating ever again. 


If she is a close friend, you should be able to just explain that you regret cheating and won't do it again and she should understand. If not, my advice is to do two things. 


First, gather your evidence so that you can prove that she is also guilty, and potentially even guiltier than you. Make sure you have enough evidence that she's can't pretend she is innocent and you are guilty. 
Second, address the situation head on. You have two options here:


Own up to it. Tell the professor everything, show him your evidence, and take your punishment. Hopefully they will only lower your grade rather than failing or expelling you. 
Confront your friend. Tell her (in writing) that you regret having helped her cheat, that you won't do it again, and that you're prepared to take the evidence to the professor and get both of you in trouble if she won't let this go. Don't get drawn into a big fight, just give one-sentence responses (something like: "I understand your position, but I can't keep helping you cheat; we either need to stop this once-and-for-all or else turn ourselves in.") 



Some would say the first way is the only way to behave ethically, but the second is likely sufficient if you never do it again. Whatever you do, don't continue cheating or letting her blackmail you. Good luck.