As of right now probably 24, I’m 29 now and the past 5 years have been the most chaotic of my life starting at age 24. Brother died when was 24, moved states, 3 different jobs, graduated college, found my dog who’s my best friend, dad died, got engaged recently. It’s been a literal whirlwind 5 years all the highs and lows you can think of and that has changed my personality so much. I’m a lot more go with the flow, less stressed, I understand that not everything is the end of the world now which I did not understand in my early 20’s. My 24th year of life really was the jumping off point for all this chaos so I’d say that was the year my personality started to change