What should i do?! i think i like the school nerd.?

Honestly, it sounds like if your friends would not accept a nice person just because he's not "hot" or whatever, then you need different friends. Act on the crush however you feel is right, and if he likes you too then eventually you'll end up introducing him to your friends. Maybe they'll be cool about it. But if they aren't then it's an indication that you could have better friends. You deserve to be with a guy who treats you well, and he deserves to be respected for his good qualities.