SHOULD I DATE MY FRIENDS BF??

Liv
PLEASE READ I NEED HELP WITH THIS‼️‼️
Ok so don't think that I'm a bad person or anything, read this first.
So last year there was this kid that I had a crush on and I really liked him but I didn't want to date him because he was immature. But he was someone that could make me laugh and was goofy like me. I've never meet someone like that before that made me so nervous but happy when I see or hear them.So we both liked each other but we were to nervous to say anything so we never dated. Then he moved on to my friend but she didn't know that we had anything going on. So the next school year comes and they are dating and everyone calls them a cute couple blah blah blah. So we have a class (the guy)together and when she isn't around we flirt. Ik that's bad but it's not heavy flirt it's just like if he push me I push him back or I will touch his stomach or he will tickle me.  So I don't know what to do because if they break up should I try to get with him before I graduate or should just let them be and not try to date him??? I'm confused because I really like him and I have never had someone like me like this before. And I tried to stop liking him I even avoided him but when I see him he grabs me around me waist or gets in my face I just fall back into liking him again. Please help me figure out what to do.