Going back to Uni as a mature student is not for everyone. It basically means putting the pause button on life until you leave, just when your peers will be moving up in their careers. Don't rely on that as a fallback, it will be a much harder slog than going now, but for different reasons.
My feeling is that the best time to go to Uni is as soon as possible! Worry about flying when you stand a chance of developing a 'Plan B' if things aeronautical don't go as well as you hoped.