Wibblesworth.
Ditto all the comments above. A long time ago I know, but I was about 12 when I decided I wanted to do it.
With a useless degree (for ATC) under my belt, I was 23 when I finally started the course, which was the hardest part of it, and also very enjoyable too. And you get paid to sit in classrooms!
As AyrTC says, the one application per lifetime thing is odd. I could understand that if the ATCO course pass-rate was 100%, but it isn't. The pass-mark for all the ATC course exams is 75%.
If you can commit to all that has been said above, it's one of the best jobs going, with some of the best work-colleagues you could wish for.
Go for it.