I like this guy and i want advice?

ok so there is this guy and i like him alot. he is a total player but i feel like i can change him. he is a junior and he is eghteen. i am a freshman and im fourteen. i know its a big difference but i think he likes me. he flirts with me all the time and gave mehis number. i flirt back but my friends that have known him through older siblings have told me he would just use me but i cant get him outa my ead.. what do i do?