Fuck what everyone says. I went 11 years without a sibling so when my sister was born I wanted to do everything I could to help care for her and that included diaper changes. I changed her diapers, made her bottles, bathed her, dressed her, put her down for naps, got up in the middle of the night when she cried, packed her diaper bag, and carried her everywhere because she could walk for a while due to a foot abnormality.

Nothing about that was inappropriate beyond the fact that our bio father and her mother used me as a 3rd parent because I was so enthusiastic to just be involved. Doing those things for her was entirely appropriate, how often I had do them was the issue.