I messed up with my boyfriend. Any ideas on how to make it up?? (Please answer, I will choose best asap)?

Well first of all, you shouldn't worry at all. You told him how you feel, and there's nothing wrong with that. If he's concerned with how your relationship will turn out because of past relationships with girls, constantly remind him that you'll always be there for him, and you'll try your best to keep him happy, if you really do care. But don't rush him in to feeling the same way as you because that would obviously just make things worse. Give him time, and just let things flow, and he will surely end up falling for you for real. However, he really shouldn't let past relationships get in the way of how he feels for you, because none of those girls are you. If you really want to make things work out between the both of you when you leave for new schools, try your best in your relationship, and treat him right, and you'll get the same in return. Things are harder when couples are apart, but it works out if you let it. Since you two are both worried of losing each other, I doubt you'd have serious problems in the future. Just remember to let him be, and see where his feelings take him, and in the meantime, you both can still enjoy the company of each other. And it's not a warning, he just wants to let you know that you shouldn't give up your guys' relationship because he still believes that there's still time for him to fall for you. So don't give up on your relationship, and stay strong!