Rob...... just go for it! Don't hang around just 'cos you're worried about being too young!!! The airline I used to work for had Pilots as young an 19 and 20. What counts is experience, and if you get it at an earlier age than most, then good for you! I wish that I started flying at an earlier age (I am only 24!) instead of faffing around with all the ifs buts and maybes.
Take it easy.... and DON'T delay!