I had a sim as a toddler play a bunchhhh with her IF doll and it aged to a kid no problem and was walking around with her and everything and then as a child I had her play with the chemistry set a lot...
@Mikezumi yeah i use save as and my last save is her birthday, i just didnt wanna go back cause i dont know how much i have to go back. if karritz's method doesnt work then ill revert