I would say go for it, if that is really what you want to do. I think alot of people that have decided to bite the bullet and go for it, have had to make sacrifices in order to fund their training, whether it be sell a house, or take time out of their lives to save the money.
I think it all depends on your circumstances. I am not an airline, but I don't think not having A-Levels will affect you, friends of mine who don't have A-Levels have jobs.
All the best and good luck.