Ok so longish story but I really need help.

So I was like flirting with this guy a lot and I thought he was gonna ask me out and stuff. Anyway about a month later he starts hardcore flirting with one of my friends and it kinda made me feel like shit.

Anyway fast forward to now... He flirted and I think wanted to date that friend... but he asked me to be his girlfriend IN FRONT OF HIS FRIENDS(aka dickmove) anyway I said yes because a) it was in front of his friends and I didn’t want to hurt his feelings b) I think he’s nice and funny and hot and all but I’m real insecure and I feel that he really likes my friend still. I’m 16 never really had a serious boyfriend and I don’t wanna be like this but I am.

Help please

Love you all