Maybe she's 'faking it till she makes it' ? She - (like me) might actually be more reserved and takes a while to get to know people.
I bet she's a lovely lady really - she was sensitive enough to make you feel welcome in your first visit.
Get to know the other members and enjoy the group.
Aside, Re: Face-blindness;
I have a friend with this. Last year as I was driving, she was riding towards me on the cycle path. I didn't wave knowing she wouldn't recognise me & didn't want to blow the horn in case she fell off.
A few days later she mentioned seeing me. Embarrassed, I explained why I'd ignored her.
" I didn't recognise you, but I knew your number plate" ??