I'm thinking of buying entry level DSLR Nikon D3500. I haven't used DSLR before, so I'm not sure if it is a good decision to buy DSLR. I would like to know if with this camera I can shoot portraits with blured background such as on the new smartphones with two cameras. Another thing I want to know if buying DSLR is good for beginners in photography and amateur photographers and is it worth the money.

I'm new in this community, so I'm not sure if this is the right place to ask this question.
['https://photo.stackexchange.com/questions/108713', 'https://photo.stackexchange.com', 'https://photo.stackexchange.com/users/85164/']
I had an entry level for years (Canon 550D) and I have taken really good shots on it. Although lenses are important, I would like to enumerate a few other factors (sorted from the most important to the less important) that will influence on your results

1. **The subject**: This is by far the most important of all. Your cellphone can make a much better picture than your camera if you point it to the right subject. I have wasted a lot of time taking pictures of not so interesting subjects and thinking about saving money to buy a better camera until I finally discovered that it is a much better investment to spend that money on short travels to parks with view-sights and animals, or neighborhoods with cute streets and interesting people, etc etc.
2. **Light and weather conditions**: Remember the park I said you should go? If you really want good results, you should check the forecast, go really early in the morning or maybe after rains, it depends on what you want, but this the right conditions will add the right "life" to your photos
3. **The lenses**: You may be in the right place but maybe the right light you want is something that just doesn't occur naturally. Or maybe you want to be much closer to some animal, or to take a much wider picture. For this, you have the lenses. An f/4 outside in a clear day can make really good pictures, but an f/2.8 will let you work under more severe light conditions. However, an f/4 is much lighter than an f/2.8 and this may allow you to make longer journeys. An 70-200mm will make you fell amazed on how much close you can get to some subjects and a 16mm will let you make excellent wide photos. And good lens are forever. They will always do their job and you can sell them well if in good condition. They are an instant change in possibilities: you change the lens, everything changes
4. **How you use your camera and lenses**: You have to know your equipment. To know where are the button, the limitations, which possibilities do you have and so on. After upgrading for a better camera, you will feel for a while that you were more capable with your old camera until you get to know your new one
5. **The camera**: Finally, the camera. In my experience, a better camera gives you a better ISO, better shutter, more durable components, more functionalities, more photos per second, etc. Not necessarily a better sensor, for example. The better camera will make it easier for you to go further, but if you don't have what I told you above, there will be not a lot of difference in your results.

Best thing I can recommend in order to achieve maturity as a photographer so you finally feel that your entry level camera is limiting you is to go outside and take pictures. Just go out for it every weekend and you will start to understand the places, the lights, your equipment. After that, the day will come where you will know exactly why you need a better camera and what camera you need. And you will probably keep the entry level, because they are good anyway.
A DX sensor has a crop factor of 2/3. You are presumably talking about the 18-55mm kit lens. For portrait work, you'd likely use it at its long end, giving you about 83mm equivalent focal length with an aperture of 1:5.6. That will give you the same depth of field as an 1:8 aperture setting on a 35mm film camera with the same kind of effective focal length which is quite discernible but not terribly strong. You'll want to arrange your scene appropriately so that the background is indeed some distance away.

The computational blurring on a smartphone aims to emulate the visuals of quite smaller depth of field, namely larger sensors/aperture. If your viewing device ends up being a smartphone, you'll not likely be able to appreciate the much more natural action of optical object isolation (but due to camera and lens parameters, more subtle) over computational approaches, particularly since the small display scale increases the perceived depth of field.

If you are going for print, things will look different already, however.

Is it worth the money? It depends on your purpose. If you don't intend to throw further money at the problem of doing portraits (namely buying a suitable prime lens or a less basic zoom lens), you'd likely be better off with a 15-year old Sony DSC-R1. It has about the same sensor size, goes to 120mm equivalent at 1:4.8 aperture. Its age has definite implications for handling (no image stabilisation, so tripod wanted), speed, storage media, convenience, autofocus, sensor resolution (10MP) and sensitivity (ISO400 is where noise starts) and so on. But for your principal criterion of a small depth of field at reasonable image quality in portrait situations, it will deliver more than the D3500 with a kit lens, but you will be left without an upgrade path.

Of course, analog cameras will deliver effortlessly in that category at quite cheaper secondhand prices but handling film is a hassle in comparison. Even if you do want to end up using film, learning your photographic skills using digital first is going to save you a lot of time and money.

To summarize: you want to throw money at a problem. The direction you are planning to throw it in is a good starting point but you'll need to throw more in that direction before achieving your goals. Partial goals may be achieved cheaper by throwing in a different direction first and thus getting a good idea how and where to throw larger wads of money for best effect at some later point of time.

Buying your learning gear preowned often means that as you develop a good idea where you want to be heading for real, the gear retains most of its resale value. Newer gear often is more supportive with regard to getting good results with moderate effort, however.