*** don't ask us. Set up a little coffee date to spend some 1on1 time together. Just say after class that you've got some free time and that you're bored, and then ask him if you wanna go grab some coffee from Starbucks. Go together, get a drink each and then just sit and talk. Get to know each other.
Ask him out and spend more than a few minutes before class with him. Get to know him better and then you'll get a better perception of him being gay or bi. Good luck!