Around like 28-30 maybe. I had a sort of early-mid life crisis and dealt with really bad depression, ended up changing a lot in my life because of that as far as my attention to mental health. I changed jobs until I found one I felt was the best fit, started writing a bunch and self publishing books, lot's of introspection. It also took quitting drinking for the most part, as my wife and I were big partiers. I'd say I feel more mature every day now, but it's a slow process.<p>Most , I think if it's not forced on you at an earlier age, it's a decision, not something that passively happens to most folks. Until I deliberately decided to become and adult, it felt as though I always dreaded it. I'm privileged, though, and hadn't gone through any long term situation that required me to grow up before I was ready.<p>As a final note, I'd say a lot of it was working with older folks I looked up to and respected that were mature. Surrounding yourself with those who behave the way you want to is a good way to learn. Behavior is an interest, just like other hobbies.
I defined maturity when I could see 5 minutes into the future. 38 for me.<p>Before that, I used to drive over 150 mph in my Porsche on a fairly regular basis. (Every week or two.) I'm male.<p>I got pulled over for speeding and got let go. Could of lost my license.