Does he love me? sorry its long?

Okay so I have been friends with this guy for like 3 years now and he's like my best guy friend but we always flirt ..like big time flirt....we have never hooked up or anything like that but the other day he told me he was in love with me and I think I'm in love with him but I'm only 16 so idt its logical to be in love at my age and he's suuuuuper flirty with a lot of girls not to mention he has a gf so if he decides he wants to be with me should I go for it cuz he's kinda hard to trust cuz he has cheated on his gf befor so yea idk...HELP