The answers to all your questions are already available in this thread, in the old CTC thread and in other FTO threads.
For other schools, check out OAT, FTE, Cabair etc. There's plenty of places willing to take your hard earned, and a variety of funding options. Rest assured, CTC is not your only option if you are switched on and determined, as reading around on here will demonstrate.
CTC will take people with little or no prior experience provided that they demonstrate the qualities, motivation and the knowledge/prep they are looking for. They are quite open about what they want, there's no tricks involved in selection.
Turning up and saying "I don't know much about this lark, but I wanted to do it as a kid" is not going to get you very far in an hour long interview, so if you feel you are not ready, perhaps delay and spend however long it takes to become ready. The way it worked for me recently was that they get you to try and agree a phase 3 date at the end of the phase 2 tests (you find out the results before you leave phase 2), and they were as short as a week and as long as 3 weeks away.
With regard to the maths (this may sound cocky but it's my honest opinion - flame me all you want) it was comparable to GCSE standard. Applying sound exam technique helps as well.