Hi! I don't think past B1/B2 refusals should hurt your F-1 status as long as you are enrolled in the U.S. university and get appropriate documentation from the university before your interview. It is mostly easy to get a student visa but, it might also depend on the country you are coming from.
Personally, I was denied an H-1B visa after I worked 1 year on OPT. While working I applied for graduate school and got into JOHNS HOPKINS UNIVERSITY. After I got admitted I applied for the F-1 visa and got it really quickly and unpainfully. However, I didn't leave the U.S. during this whole process so it might be different for you.
Good Luck!
