Most kids who have no mental health issues or incontinence issues are potty trained and are not wearing diapers during the day by age 3 years old to 4 years old.
Some kids are even potty trained by age 2 years old and some by age 3.
A child that is age 5 and still wearing diapers during the day is not normal and the 5 year old should be potty trained.
Although if I had a kid who was not wanting to potty train at age 5 or above and I was just keeping them at home for school then I would probably just let them wear diapers and would not push the issue until they reached age 8.
But most kids will decide to stop wearing diapers before age 5.
Diapers are not just for babies and even adults wear adult diapers so it's really not a huge deal if your 5 year old is still wearing diapers during the day.