Dont be discouraged.
You dont have to be massively qualified to get in to F1, Its a myth.
Sure it helps, but take this for example.
A guy who left school with below average grades, got a job sweeping the floor for a race team, then got the chance to learn composites and now works at the races.
Its not always what you know, but who you know!
I never dreamed I would ever get the chance to do anything like that when I left school, but within 8 years of sweeping the floor that first day, I found myself at the track.
Write letters to teams, it cant hurt!
If you do nothing, you will never get the chance.
Good luck, and dont give up the hope. (you never know)