What does peach have that pauline doesnt?

What mental issues does she have?

A functional democracy.

How do you know it was her?

Pauline is Mario's Mom. Mario is actually Mario Jr. as his dad was the one who saved Pauline from Donkey Kong a.k.a. Cranky Kong. Donkey Kong is actually the Donkey Kong Jr.

why does she look so young then?

>implying they don't have threeways