"They're only little"
Ava is four. Of course you do her shoes. The sentence is true and it has an expiry date, and the thing I'd ask you to notice is that the sentence doesn't expire. It updates.
At four it's "they're only little". At nine it's "they've got enough on". At fourteen it's "they'll only make a mess of it". At nineteen it's "they're stressed with the course". At twenty-four it's "the housing market is impossible". The child changes and the reason changes and the hand doesn't, and if you're honest about the first year of your own adult life, you may remember a parent who was still making the phone call.
There's a body of research on what parents of young adults do, under the name overparenting. Chris Segrin and colleagues surveyed six hundred and fifty-three pairs of parents and their adult children across the United States, and defined overparenting as directing, assisting, problem-solving and monitoring at a level that doesn't fit the child's age. The parents who did most of it were the more anxious ones, and the adult children on the receiving end reported poorer ways of coping, which in turn went with more anxiety and stress. It's a survey, it's one country and it can't tell you which way the arrow points. But the finding about the parents is the one I'd hold onto. The takeover, at that age, tracked the parent's anxiety and not the child's need.
A later study from the same group, Jian Jiao, Margaret Jane Pitts and Chris Segrin, asked a narrower question with two hundred and fifty-six parent and adult child pairs. Were parents adjusting how much they did to how much their child wanted to do for themselves? The answer was mostly no. What parents reported doing wasn't related to what the child reported needing. The researchers' reading was that parents may overparent to meet their own needs rather than the child's, and that's a cautious sentence about a survey and I'd keep it cautious. But it's the same shape as the hand at four. The hand doesn't check first.
None of this means that a nineteen-year-old with a parent who makes their phone calls is doomed. Most aren't. What it means is that "they're only little" is a reason that has to be re-examined every year, on purpose, because it won't retire on its own. The habit is happy to be twenty years old. The question to ask, at every age, isn't whether they're little. It's what a child that age can do badly, and whether they've been allowed to.