Well I have taken the entrance exam for a local tech school and I passed. I am looking into taking their computer networking and repair course. I can't start until next august though. And they recommended taking some math classes. Not quite sure where or what they meant by that.
I would also recommend taking some math classes. I used to proctor a math placement exam, and ninety percent of the people who did poorly, were not dumb. They just didn't know how to do certain things. If you're going into networking and such, it would be a really good idea to get yourself VERY comfortable with numbers. Networking isn't always solving equations and stuff, but the logic is all applicable.
I'd take a 98-level course (the sub-100s are usually 'remedial' and don't count toward graduation), just as a refresher, make sure you're absolutely solid on those concepts. Then, into the algebra, geometry, etc. You probably don't need, like, calc and stats or anything, but the more math you take, the more confident you'll be in, well, everything. Take it from someone who really, really, really regrets not taking more math courses.
I didn't "NEED" them, so I passed them up. And I really wish I hadn't, because now, numbers make my head spin, and I can't do anything with computers like I wanted to.
Good luck, I know you're going to do fine!