[Celyn]

I pretty much agree with what Katie has said. The cut off points for birthdays and such for starting school can mean that some children are a year younger than most of their classmates. And as you get older, it's very common to have an extra year in school, or to start college later and be in classes of mixed ages.

However, regardless of age, everyone should be treated equally, and not singled out for some reason that may not be true (your question of whether people would assume the person was held back).