What a wonderful vet!!!!!
Refusing to vaccinate until they are sure she is old enough is sooooo nice of them. She could go into heat before then and she could be spayed after about 4 months since she is over 2 pounds. I don't know why they didn't, but they aren't comfortable and that is excellent that they didn't do it when they don't feel it is safe!!!
Maybe they hope she will get a bit bigger.