I'm a 20 year old man who has been wearing women underwear since a kid
You wear them everyday? You keep it private, right?
Yes, I wear them to sleep everyday. I think it's a part of me.
Wearing what feels comfortable to you is fine. If wearing ladies undergarments is what makes you happy then you should continue doing it.
I'm glad you don't have an issue with this. I'm normally shamed for it and it's the first time someone is okay with it.
If your behavior does not harm or offend anyone I think you should do what makes you happy.