What are good tips on writing a character whose 27?

I am writing a super hero/modern show ala DC inspired by new Superman and had a 27 year old character and wanted tips on writing them

1. So how diff are they from early-mid 20s character or is there an overlap?

2. is writing them as enjoying their youth or cocky etc or jokey too immature

for example are they part of the younger hero crowd or more older (for example superman in movie is 30 and there's lantern and hawkgirls on younger side)

3. Where can they be in life? is a job fine and not be married or owning a house such as apartment good too