my child is never ill

I have a 16 month old daughter, she's hardly ever poorly at all. My friends and family all say that it's a bad that I don't let her get poorly or be around children that are poorly. My niece seems to pick every illness up (cold after cold, chickenpox, impetigo, hand foot and mouth, cold sores) and whenever my daughter is around her and she gets a cold..forgot to mention my niece is 3 1/2 so she' in nursery now so she's with all children passing bugs about. Anyway my family say I'm wrong for not jetting my child be around her whilst she's poorly and she needs to catch it sooner or later but I always say I'd rather her catch it when she's in school naturally and keep her away till I no she's better. Does anyone else feel the same as me or am I in the wrong???