Happy birthday! I turned 40 on Sunday. Seems these decade birthdays give a bit of retrospection, I know they have for me. My 30th and now my 40th have caused me to be a lot more introspective and retrospective in thinking about who I am and what I have done in this amount of time.
You're lucky to have let go of regrets, I am still trying to learn that one.
Letting go of regrets is the only way to be content in where you are. Also, if we simply regret wrong decisions, we often don't learn from those decisions. As I get older, so do my children, and I am having to put all I have into them, making sure they grow up into godly, respectful/able young men and ladies/mothers.