Are INFPs childish?

I was just looking up some of my fav shows on personality-database.com, and as one does, I was searching for characters who matched me specifically. I'm an INFP (4w5), and on the site, there is a large amount (from what I saw) of either children or the past/younger version of an adult character characterized as an INFP. I don't really know much about MBTI and I don't really take it so seriously. I'm just curious lol.