Im 20 and have been on the line for 4months and loving every moment of it. If you want to do something, go for it.
With interviews although you won't have this so called "life experience" you can always use and adapt situations from school, work, air cadets, clubs, groups or anything you do in your spare time, so don't let that worry you.
The only down side of youth, if you go to Oxford flight school you will have a few 'dry' months in Arizona (if under 21).
Best of luck.