I've helped a relative adjust status through marriage. Basically everything you are lacking (joint accounts, etc) will be questioned during interview. It all depends on the interviewer and their impression of your relationship. My relative was questioned about why they did not file joint tax, why they did not have joint major credit card (they only had Target and Walmart), etc. Just be prepared to answer those questions.

Does your boyfriend have a stable income? He would need to prove that he has means to support you. If not, you would need to find a cosponsor. Just mentioning this since you guys are still in college.