Firstly, well done for getting out. Some of these cults /religions/groups are not easy to get out of. Even though I wasn't in a cult, I've often looked back and wondered the same. I've still got ways of thinking that I sometimes automatically default to and I have to consciously be aware and make a decision to go against it. So, if I were raised secular, I would have had a much freer mind, if that makes sense.
On the other hand, I could have still been trapped there today and only left closer to my death or worse still, never realised. That's another very possible alternative and I compare against that.

Regret, to me, is knowing the right thing to do, and not doing it anyway. Being true to the insufficient light you have at the moment, can be a source of disappointment but not regret.

I deconverted at about the same point in my life from what was a less cultish, more conventional brand of fundamentalist Christianity. And like you, I feel I'd have been much better off if I had done it much sooner, or not been caught up in it at all. But what happened, happened and can't be undone. The train left the station. So being consumed with regret is just going to make matters even worse.

From my mid 30s on I spent maybe 15 years prying bad thought habits and ideas out of my head with a crowbar -- both unlearning years of ideology and operant conditioning, and installing replacements. Unlike you, I did have children who were negatively impacted by all this. So it's been the gift that keeps on giving.

But ... I have moved on, I have a family, a meaningful professional life, and I am completely free of the ignorant and failed epistemology of religious faith. Better late than never. Focus on what you have, not on what you lost.