Not all countries will adopt a bitcoin standard at the same time and if they do, will they educate their people about bitcoin in the right way with self custody... or will they teach them to buy only regulated ETFs with banks and make bitcoin in self custody illegal for individuals.
Discussion
Of course, anything can happen. She will have to figure it out 18 years from now, there's nothing we can do.
One potential issue is quantum computers. If that happens, meanwhile, she needs to call for help from someone (I'm assuming we are talking about a child, or she won't study bitcoin in the meantime).