Umm...actually...
Nope. Not Catholic. I'm perfectly happy being just a plain Christian. I don't belong to any denomination. I used to go to the Methodist church, but that was when I was little and when I would probably say, "Jesus? Who's Jesus?" I didn't know very much about Him back then, and I was just looking to have a good time with my Sunday school friends.
Actually, no, we're not all God's children. I believe Jesus made that clear in the Book of Matthew, although I may be wrong. We don't become God's children until we repent and invite Jesus to be our Lord and Savior. Then we are adopted into God's family. Up until that point, we are children of wrath/Satan.