You and your friend like each other and are attracted to each other, but you don’t want to date her because you want to focus on your studies instead.
Well….it’s pretty simple, but you’re not going to want to do it. If your studies come first then you shouldn’t see her any more or have her in your life. Your attraction to her and hers to you is going to be a distraction that gets stronger and more disruptive as time goes on.
However, my suggestion is to practice balancing your work and your personal life. This is the way you’ll be successful in the rest of your adult life: balance. I’d suggest that you ask her out on a date and see if she’s interested in dating you. I suspect she’ll say yes, but if she doesn’t, then you’ll know she’s just toying with you and you need to move on with your life without her because she’s too distracting. But if she says yes, I think you should try dating and being a student.
If you intend to marry and have children and support your family, you’re going to have to balance a lot more than just dating and being a student. Your future work life, marriage, family life with in-laws, your own family and your future children will take a much bigger toll on your ability to focus, so start now by learning the art and discipline of balance. It’s a skill that university doesn’t teach you — but I will! 😀