"6 year old girl with a baby boy on her lap"
Rita suddenly feels the weight of Aaron on her lap greatly increase. Well now that's she's seeing her surroundings, everything seems to have increased in size. Looking down she realizes the truth. Her body is that of a little girl and her uniform has been adjusted to fit. Aaron looks up at her expectantly.
"Go?"
"I did can't you tell?"
Aaron examines his friend. Everything seems normal. Rita's hair was still in pigtails, front tooth still missing, her mom still insisted she walk around with a name tag on her chest in case she got mistaken for a lost kindergartner and not a child prodigy. Aaron shakes his head.
"You've got to be kidding me! How can you not tell?"
Aaron is startled by the yelling and starts crying. The two's homeroom teacher, Mrs. Fletcher, walks into the gym and frowns at Rita.
"Rita I know you're excited not to be the youngest star pupil, but you need to be careful. Aaron might be as smart as you, but he's still just a baby."
Rita nods sheepishly and sticks a pacifier clipped to Aaron's uniform in his mouth.
"Ok now come on. The halls are clear now, so you two can head to class."
Rita stands Aaron up and takes his hand, still holding his phone in her other. She's a bit disoriented still, but has led the boy to class enough times that even as a little girl it's not too hard. Aaron on the other hand is grumpy, Rita didn't change anything obvious and hasn't given the phone back either.