Not every situation calls for opening up and spilling the beans on content regarding ageplay/diapers. Some families take it better than others.
I did not have an understanding mother growing up, at least in regards to understanding odd or different interests. I had a couple of confrontations - finding a receipt for Pampers, approaching me about a pacifier in my room, etc. My tactic was deny, deny, deny. Wasn't my receipt, was attached to another receipt. Pacifier was an old toy for one of my dolls, and so on. She definitely didn't buy the receipt excuse, but eventually dropped the face-off because I never changed my story. It was much better for me that way.
People get all sorts of reactions, but use your best judgement on what kind of approach you want to take. I know it wouldn't have worked in my favor, ever, if I tried to explain logically about ABDL-ism because of my mother's personality and beliefs.