Question regarding a crush of mine

So im a demi (tutor) for this one first year university physics course. And i have a major crush on one of the students.

Should i ask her for her number or to get a coffee. Or is that unprofessional, considering i have to mark some of her tests and explain some of the work.

Im busy with my masters is physics and shes a first year.

The age gap between us is around 5 maybe 4 years. Would that also be a straight turn off causing her to say no?

Any advice would be appreciated.