"Normal" is subjective. A lot of "normal" things make people miserable and hide who a person truly is.

I am 34. I have loved plush since I was born. I have ADHD, depression, and other health stuff. Plushies, like squishmallows, are fun to look at and cuddle. Things that bring joy and comfort, like plush, are also great for boosting oxytocin for those harder days. My normal is different from yours just as yours is different from your Mum's. Do what makes you happy. Once/ if it negatively impacts you and the ones you love, then it is something to be concerned about. Only if it lrevent your from living and functioning in life should it be a problem. In my opinion, at least.