25? Really?
Marian Paroo must be at least 26 ("I'd say 26 years too late", and given that the reference is not to her age but to when her first visit to the footbridge should have been, it's much more likely 30-35. Now, we don't know the exact ages of anyone in this flick, but we do know the ages of the actors: Shirley Jones was 28, Ronnie Howard 8. Nope, I've damned sure never heard of anyone having a baby at or before age 20. All that said, this is not the usual case of laughing at such speculation...