From my own experience and the experience of other people I know, most speech therapy doesn't really work as promised. And then they accuse you for not practice enough and then you feel horrible for both failing and wasting your parents' money (and speech therapy might cost a lot of money). So in my opinion, you shouldn't regret not going to a speech therapy and absolutely don't resent you parents for that, it only makes you feel worse and not help you at all. It seems that you are on a good path with your life and career so just keep going and working hard towards your goals. Good luck!