I can relate to this, I'm 24 and sometimes I act childlike and immature, my boyfriend doesn't really mind. I've sucked my thumb since I was a baby the only time I've stopped was when I was in regular therapy. So it seems to be something that goes when I'm feeling better mentally.
I've had stuffed toys since I was little too, not the same one, I usually buy new ones. My current one is Chikos, I like her because I think she's cute and has odd eyes and one wing bigger than the other
(couldn't take a decent pic so here's one from t'interweb)