C.P.
Hi M.,
I think this is completely normal. My daughter was 5 months old when she first showed signs of stranger anxiety, it was towards her grandparents we went to visit in Finland that she hadn't seen but once prior. She quickly grew to them though, although it did take a while. I think it comes and goes too. Sometimes my daughter is fine around strangers and other times she is very shy and doesn't like to be held or left with anyone, even if it's people she is familiar with. I am sure most moms here will agree with their experiences. Just stay calm with it and don't feel like you need to constantly coddle her if she starts crying. Or else it may be more difficult for her to get used to being with someone else. You're not doing anything wrong, rest assured! :-) Your mom just needs to give her a little time to warm up to her. Sometimes it can take my daughter a whole day to warm up!
-Char