Good Lord, what a question after 50 years of reading! *LOL* I shall take the easy way out and chose my childhood heroine, Trixie Belden. I've already talked about Trixie in previous days of this challenge.
Trixie was cool. During the books she was 13 and 14 years old, which suited my preteen sensibilities perfectly. She was the only girl in a family of 4 siblings. Two older brothers and a younger brother. As an only child, I envied that. She had a special group of friends and they formed a club named The Bob-Whites of the Glen. And she solved mysteries.
Well, that doesn't sound like she and I had anything in common, but the thing is, Trixie made mistakes. She blurted things out without thinking sometimes, things that came from a good place but came out wrong. She had a temper. She rushed to judgement at times but was always quick to apologise when she was wrong. She disagreed with her parents sometimes and got in trouble. She did chores. She was a regular gal and THAT is what I related to.
(And really, she was much cooler than that other teenage detective, Nancy Drew.)