I agree with @juilet on all of her points. I should just mention that the CS GRE was discontinued.
I can add that you do not have to go to grad school for CS. Depending on your goals it may be a better move to go to work. Especially if you come from a strong CS program and Stony Brook seems to have a strong reputation. Your parents are right. There are lots of situations where the work experience is as valuable as the MS. Or your time doing an MS will be better spent after working, when and if you have a CS focus you have identified that you like to work in. Or your employer will pay your MS later. Getting a PhD has some of the same considerations. I’m just saying to keep an open mind. But it will only help you to be prepared should you want to do grad school and getting involved in research is important.
Some early work my dd did was just crunching numbers and preparing data for use by grad students for research. That kind of work can just get you familiar with the kind of projects there are and getting some background on what CS research is, the kind of problem they are working on. Some advanced research involved building a library that contained functions retrieved by other programs, then rewriting the library in a new software language she and her partner developed to make the library more efficient. Working on algorithms that will make the program run faster etc. This involved taking extra classes to understand the math involved.
I think a lot of things will be clearer to you in a year and I wouldn’t worry about these sorts of things for a good year. But I would read about the kind of things the professors and grad students are working on, read the dept webpages of the research groups and the webpages of the faculty.
Elsewhere you recently said you were interested in being a premed so if you mean that type of grad school, everything changes.