One thing to remember is that your still young and you will have many relationships.....Your boyfriend is in college but the only way you can have a relationship with him is to trust him. A great relationship can only work with trust. You need to trust him and not worry about what he is doing in college, as I bet he worries about what your doing in high school. So talk with your bf about trust and tell him about your worries and see if your both at the same level...
With guys hitting on you, that is great for anyones self esteem, but always analze what kind of guy they are....To be honest, I was a player type in high school only looking for one thing, getting laid.....Girls look for love, so think what kind of guys are they and see if they want the same thing you do....
I hope any of those helps you, take care.