To me or at least
Babies 0-2
Toddlers 2-5 since they can talk, have a personality, walk, and watch TV/use tablet
Children 6-12 because they go to school, can enroll in after school programs, build some schools but they can't cook or do much at home alone.
Teen 13-18 because they can date, they can apply to scholarships or universities, they can go anywhere else.
Young Adult 19-35 where you can go to college or work or start your family.
Adult 36-64 because now they're getting older, wrinkles, they're told to think about settling down, a lot more whims related to careers or family.
Elder 65 where you can retire or work until your last days. No longer able to have kids.