A woman's fertility starts declining at 27. After 42, it's a cliff dive into barrenenss or menopause. Our grandmothers didn't have kids in their early 20s because they were stupid. Liddy was talking about this on his news review this morning. My advice, be smart, marry a "man", have kids in your late 20s and be young enough to enjoy all that brings including grandkids someday. It is very tough to "have it all". Some do but they can afford nannies.
Of course I'm 44 and still have babies coming....I'll be an old man still raising kids. I am eternally grateful for that. Were I a 44 year old woman....it would be much more of a stretch.