K.F.
She's fine. She is getting adjusted to a new situation and new people. Some people as slower to adapt than others. It is my guess she is probably an introvert which means she processes life internally. As long as she can convey her needs and wants she will be fine. She doesn't necessarily need to talk to make that happen.
I'm an introvert and throughout my life when I meet new people my first response is to fall back and be quiet especially when there is a room full of people. There are times when I can be quite talkative and seemingly outgoing in situations where there are tons of new people but in most cases I know weeks in advance that I will be in that situation and can prepare myself accordingly. After that interaction has ended I rush back to my cocoon to rejuvenate. Most people that know me would guess I was an extrovert but I'm just a really well adjusted introvert.
My guess is she needs more time and more patience. As long as her silence isn't a problem she should be fine.