Dazza,
To help put your mind at rest - you are really not that old to be embarking on a flying career. I am at one of he integrated schools in the UK and the average age is somehwere in the mid to high twenties - with a fair few students in their thirties.
The standard of the Maths/Physics required is not much more than GCSE so don't worry too much about that - you will be fine.
I'm a similar age to you and was also anxious about the level required before I started but all has been ok - as long as you are determined and have the time to commit to study you shouldn't have any problems.