Like a girl...

Big Bro evidently has some confusion about the difference between boys and girls. Recently we've had lots of comments along the lines of:
- I'm going to write my name like a girl.
- I'll start school when I'm a girl.
- how old will I be when I'm a girl?

As far as I can make out, it seems that he equates "girl" with "older". No idea why! Oh, for a little window into his mind...