I'm hot for my ex-teaching istant but idk if he is gay.....HELP?

So he is no longer my TA and idk there was (I felt) some ual tension building up over the year. I went to almost all of his office hours (for of course help with my HW) but I could not help feel that there was some attraction. I caught him staring at my lips a couple of times and we teased and joked around a bit but always kept it very professional. A couple times he would blush and turn really red when he saw me as well and we'd make brief but intense eye contact. However, even with all this, I could have misinterpreted any signals so I always had my reservations and doubts if he was even straight!! HE is european though so I can't really tell@ He dresses nicely and has some feminine qualities others say he is definitely gay but I honestly can't see it... Now that he is no longer my TA I wouldn't mind pursuing him if only I knew if he wasn't gay. Also there is quite an age difference he is a post-doc and i'm a rising sopre in college. Idk there something about the whole taboo teacher student thing him being older that makes me really want him. WHAT DO I DO/figure out if he is gay? Should I pursue him/flirt since he is no longer my teacher? Advice please :)