If you made wrong choice & realized mistake much later, it's okay. Even if it changed course of your life drastically, it's still okay. You did what you felt was best. You've already suffered a lot due to that. Fretting is a waste of time. Forgive yourself. Start afresh. You can!
We need to accept that we won’t always make the right decisions, that we’ll screw up royally sometimes – understanding that failure is not the opposite of success, it’s part of success.”