Is 14 too late to start a professional career?

Absolutely not. While you might not make it to the Olympics, with hard work, it is not impossible to catch up to the people who started at 7. It all depends on how often you practice. If you practice 20 hours a week starting at 14, and someone who started at 7 practices 5 hours a week, eventually you'll get to where they are. 'Professional' can mean many different things, though. If by professional you mean Olympic or international competitor, you might have a hard time catching up, but if you mean small time competitor or professional coach, you can start at any age.