Give yourself some credit! You are after all doing what you love now. Live in the moment, not in the past (yeah I know, even though I am young, I know how hard it is to not live in the past) and focus on what you've got now. It sounds like you have a good life.
Everyone has regrets. If you carry them with you all the time, you will never get anywhere because regrets are heavy. Live every day to its fullest and enjoy your tuba playing. That is what music is meant to be in its purest form. Also, be thankful that you DON'T have the pressure to perform as a symphony player.
