What kind of child abuse signs are there in women and was this girl abused?

In the past I met a young adult girl who was shy an introvert and didn't like going out, she was good at school and endet with a 1.9 gpa in her final highschool year. But when I talked with her something was always in the back of my mind, through knowing her and her brother I found out she very likely has no social circle or friends. Then the longer I knew her the more this question came into my mind. "Was she abused as a child?" She had some signs. Trying to please others by achieving high scores, always doing good in school, she found it hard to say no to people. She is shy rarely went out and studied often and was gaming a lot. She's very introverted and I met a side which others did not know from her.

Her brother in comparison is different from her, social and easy to talk to not introverted and not shy.

I'm no longer in contact with this girl tough so trying to help her would likely not be possible.

What kind of child abuse signs are there in women and was this girl abused?
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