I don't believe that there's much wrong with believing in Santa up until you're on your teens. I remember a couple of cousins of mine who, by the age of 10, still believed Santa would bring them toys. Of course we all have to wake up for reality at some point, and so you did... might have happened a bit later than usual, so what?

And your mother, well, she did the best she could to try prevent you from the suffering of losing your father at such young age. Maybe keeping you in a bubble of fantasy and fairy tales wasn't the right thing, but that was the only plan she could come up with. And I also don't believe that it has hindered your progress in life.

Anyway, I think that you're judging yourself too harsh, for something so minor. You're over it now, and that's what counts.

Take care.