Am I old before my time as a Mother?

I'm 36.with two kids....not ancient but not a youth or "young person" anymore...I'm fashionable and up to date with things....but I've noticed over the past few years that other Mothers of my age and older seem to extend their youth for years...I don;t mean that if you're over 30 you shouldn't go to gigs or clubs or dress nicely...but what about screaming in excitement when it;s your birthday as I've seen loads of women my age do...and expecting people to drop everything for a big drunken bash... Or acting all girly and daft over certain things...or having suggestive y pics on your Facebook page? I know loads of women who act like girls....they're my age but seem to be stuck in their early twenties..going out every weekend and getting drunk and then being so hungover they've no time for their children as they're too busy being sick. Am I really old before my time or something? I like going out for meals or to the theatre...I like having days out with the kids...I dont seem to enjoy getting drunk since they were born...am I old before my time or are some of my peers trying too hard to stay yong?