Hi! I also still live with my parents and only earlier this year started identifying as a little. But I've been this way always and most of my little things have been known to my parents and friends for a long time.
I personally don't hide anything, but I don't use diapers or pacis or something that might be questioned. I have my small pillow I've had since I was a baby for real and my parents have known how important it is to me since forever. I've made it clear that I like cute things.
I like to go for cute vintage things. My mom helps me collect things for my home someday, things like colorful old pyrex kitchenware, translucent pink depression glassware, flower-design "sour cream" glasses, etc. My purse is a Vera Bradley, a well regarded brand with loads of colorful designs. I make no secret of loving Winnie the Pooh, especially the original book version. I read Newbery Medal children's books and classics. No shame in these things.
My advice is to only hide what you have to, like sexual things or diapers if you use them. Be proud of your stuffies, favorite sippy cup, unicorn or other cute bedspread, etc. If you like to read, go to any used book sale and sort through the kids book section. Then just stick them with your other books. Why should your parents go through your room like you have contraband? If your parents say "you're too old for a teddy bear" (or whatever), just tell them it's what you like and doesn't concern them. What are they gonna do, throw it out when you're not looking?
I'm going to assume here that you have a kind, loving family and not an abusive one. Be yourself. If you're open about liking cute things, your family won't be surprised when you have cute things. And how can they complain if, for example, you have a phone case with disney princesses on it?
Sorry if I just rambled on a lot, but I'm a proponent on not hiding your littleness if it's a part of your personality. (If it's just a sexual kink that's another story). Ask me if you want other advice!
Big age: 28
Little age: 5-7
Children don't worry what they look like to others. They are 100% themselves. When we get older, we learn to fit in society by submerging those parts of ourselves that our culture looks down on. We don't want to be rejected by our parents. We don't want to be rejected by our peers. Growing up may include re-embracing ourselves even if we must stand alone.
Thank you for being here as I re-embrace the Self I'm meant to be.
(Note: I'm not looking for a caregiver right now. Please don't ask.)