Hiii ! I remember seeing you in a Discord servers
You know sometimes you don't really have to "come out" as a little. If you've always been a little childish, if you still have stuffies around and stuff, people will just think that's part of your personality. Like, you don have to hide it but you don't have to exactly tell either. Just be. Especially with your big age being 30, you don't have to justify yourself to your family. Idk I feel like telling other you're a little only works well if they're already aware that 'littles' are a thing, or say if you're in a loving relationship then you have to tell, otherwise you can say you're a big kid at heart and that'll sound fine for a lot of people. Then again idk I never really told my "family" but my family being only my mom makes it easy because she always knew me as a stuffies/toys/kids movies loving kinda person and doesn't bat an eye when she comes to my place and I'm eating in a princess plate but then again I don't leave the diapers on display either. I feel like this is the right balance of what she does and doesn't see that makes it easier for her to accept me as I am. She doesn't have to know every tiny detail.
I see it almost like, if you come out as gay to your parents they can be okay but if you start telling them the whole hows and where you do it they might not be as comfortable with it.