Your peer group is not your age group. Your peers are Japanese toddlers, not gaijin forum trolls and not Japanese people your age.
If you hadn’t been schooled, you’d know that your peer group is not your age group. Your age group is determined by your parents’ sex life — just like your nationality and your ethnicity — you had no choice in the matter: your Mom was tipsy; there was a couch; one thing led to another.
Your peer group is determined by your behavior. Your choices.
Stop comparing yourself to people whose parents got randy around the same time as yours did.
Start comparing yourself to people whom you act like, or whom you want to act like.
If age mattered like you think it does, if your peer group were your age group, then everybody of the same age as you would quite literally be the same as you. They would have achieved more or less the exact same things at the exact same time. Obviously this more or less never happens. Why? Because it’s not time that matters, it’s choices.
Only stupid people care when you wormed your slimy body out of your mother’s nether regions, and how many times the Earth has gone around the Sun since . (← Abusive assurance, a logical fallacy…yeah, that’s right, I picked today to start pointing out fallacies in my fallacy-riddled writing). And you’re not stupid.
Stop counting years. Start counting choices.