If you’re uncomfortable it’s advisable that you tell her not to. Or if she is reluctant on wanting to still kiss your babies than maybe could ask her not to have her lips directly touching baby’s skin. (Like closing lips and smelling that kind) it’s just for safety purposes as you wouldn’t know the germs we have which can affect baby and toddlers easily. Hope this helps!
Tell her for hygiene purpose don’t kiss your children. That’s how virus and bacteria spread and how children get sick.