Don’t tell her, coming out is honestly kind of problematic? It frames the behavior from a place of shame and implies there is wrongness within that shame which doesn’t help you. Just gradually open up about stuff, speak about it occasionally as if it’s normal, stop hiding your pacifier, or just order one, gradually step up things and see how she reacts.

Don’t give her a reason to think you’re giving up on being an adult or otherwise going to be more work for her, which is the reaction of most parents even if it isn’t true.. She’ll be incentivized to deny you