Alcohol helps. Kidding. Sorta.
Hell, I'unno, it went by so fast I didn't really have time to let it sink in. Now I'm too busy worrying about how close 40 is to care about being past 30, and I've barely been 30.
It doesn't mean a person can't still do the things they want to do in life, but I do notice there's a societal pressure/stigma once you hit 30 that you're supposed to have "done more" with your life, for lots of us.
Most of my clients are between 35 and 60, and many of us collectively share a joke that we all stopped having Birthdays at 27. Not sure why that seems to be the "peak" age, but that's what we seem to prefer. I guess because it's an age that's old enough to be a "responsible adult" but far away from 30 to still be "hip".
As long as I have my hair, I don't really care. I just don't go out of my way to advertise my age. I'm not ashamed of it, exactly, it's just easier not to talk about it.