You know, this might not be as bad as you think it is. Even though you want your voice to be deeper, it's actually better to have a "younger" voice instead of a voice that cracks. I mean, there's a kid at my school who's 15 and looks like a little kid. But nobody makes fun of him; at least not in an unfriendly way (like he pretends to fight people and they just grab is head and hold him 5 feet away from them while he swings uselessly
). I find that you get made fun of alot more when your voice is cracking (like they imitate what you just said if your voice cracked in mid-sentence). So don't sweat it; if the kids are half decent you shouldn't have any problems at all; that is, untill your voice cracks
By the way, are you nervous because it's your first year of highschool (i.e. new people, etc.)? Well don't worry; highschool's the greatest! Last year was my first year, and I swear it was exactly like a funny TV show!