The teenager kept looking and would find my dad staring every time.
There is not enough information to determine whether the man was staring at her because he disliked her, liked her, etc. and also no reason as to why he was staring at her, e.g. perhaps reminiscing times when he was young, wild, punk, whatever.
"What's the matter old man, never done anything wild in your life?"
This seems to be a blatant or blunt judgmental attack in which the girl assumes he was staring at her for negative or unaccepting reasons.
"Got stoned once and fucked a parrot. Just wondering if you were my daughter."
Humor ftw ^_^