She was extremely shy and tried to keep a low profile in everything she did. She didn’t like interacting with strangers and avoided it as much as possible.

Shy
being reserved or having or showing nervousness or timidity in the company of other people.
"I was pretty shy at school"

After reading this piece, and thinking I should comment about the dating experiences, this stuck out most to me the most. Your mom was an introvert. Shy is an emotion, introvert is a personality type.

And it's a beautiful thing to be that most extroverts get wrong about her type.