A'Level age limit?Watch
Don't think so, I think I remember reading that David Cameron took an Economics A-level to make the press happy, and there are plenty of adults who take them. There's also a guy from the US in my year who will be 19 when he takes his A2's.
In essence, you'll have to speak to your college about funding if you already have qualifications that are above GCSE level.
If you had been over 19 when you started A-Levels you might have had to pay for exam entries yourself (depends a bit on circumstances / school / college).
I'm in a situation where, if I don't get into uni this year I want to try again this year. I'd like to take an AS and A2 at the same time to get the full A level in one year. How does this work? Who do I talk to and what steps do I take?