Yes, she was ashamed, well she is still ashamed of doing it. What can I do to make feel more confident
It's pretty common for females to dislike squirting. For many reasons. Some feeling like it's abnormal, or that it's a soiling activity/urinaryincontinence, and because of that it brings on shameful feelings. For some that it's annoying and not really that pleasurable for them. Or that it has been fetishized in porn.
You'd have to ask her about her feelings. Her feelings matter most. She shouldn't ever be made to feel that she has to do it for your pleasure, or that there's some kind of inadequacy involved. That might ruin your relationship majorly!
My partner really enjoys it, but sometimes in the past felt performance anxiety because her partner was not secure in his performance if she didn't squirt, so she felt she had to for his ego.
Don't make an issue of it that could damage her trust in you. Establishing and maintaining trust is the most important thing.