The only real difference between your 20s and 30s is you actually have to be about something
If you were getting to it in your 20s then your 30s are fine
If you were distracted and avoided doing what you needed to in your 20s, your 30s will remind you that you are behind
That applies to fitness, money, career, etc
If you dread turning 30 and think 30s is old then you probably crashed out and what you really fear is not being able to drift through life anymore behind the excuse of “youth”
30s is still young in the context of a 70+ year life but playtime is over
Respectfully though if you’re black in America playtime was over after high school