Does anybody else find girls who act like little children annoying?

I'm not neccesarily talking about throwing tantrums or pouting when things don't go their way. Theres this girl at my school who I've noticed she acts just as childish as when I met her.. In elementary school she hasn't changed much . Like she still has a little girl's mentality. today In geometry she was up on the board "doodling" she called it and she finds everything funny and tops it off with a light childish laugh. She also is too dependent on teachers to help her. Like our teacher igned us a I mean worksheet to do and she was helping her , she was doing fine while being guided. The teacher said relax you can do this stuff but when the teacher tried to go back to her desk the girl kept saying No I can't. I don't want to be mean but I feel like saying to her stop acting like a little kid act your own friggen age! I mean sheesh your like what 16? you are gonna graduate in 2 years? Are you still gonna be in that kiddie state of mind? Because you won't get far in the real world with a child's mentality. Michael Jackson is an exception though.You can be innocent and still be mature rather than to remain naive and inexpierienced