Sorry to break this to you at such a young age. Men and women cannot be "just" friends. It never works out. You can be friends with a boy for a long time but you have to remember that he will think there is a chance between you two the entire time.
In my own opinion, him being your boyfriend is your own decision and will depend with the mutual feeling you have for each other or the manner in which he treats you, and the care for you or the love he shows to you.