I Don't get it, we flirt, we kiss, but then this.?

This guy i bn flirtin with nd stuff, he kinda kicked off the flirtin in the 1st place btw. like, we bn kissin buddies for a few weeks now. it didnt really use to have a serious effect on me. but i think i kind alike him. nd i asked him wat was up between me nd him, nd then he comes up with this lame excuse that its my last year in highschool (hes a junior), and that we shuldnt get into nayhting. man wtf!i dnt get it!