The fish/bicycle axiom was tossed at me and my little sister from the earliest time I can remember.
Funny thing is, my oldest niece Abbie (she's four, and her twin sisters will be two this weekend) is my mother's best friend. Mom wouldn't trade Abbie for my sister's career for love or money.
(Do I want my own? Yes. Do I have any? No. At 37, it's getting close to too late.)
My mum had me at 37 - you can do it!