I'm with HK...give either one or the other, age or grade level, not both. However, does it really matter that you provide a grade level? Unless it is someone important enough to explain to (and even then I don't over-explain it), "my child is X years old" is usually what they really want to hear. If they follow the age answer with "that's what, Xth grade?" just nod? smile

I have found that usually when people ask for grade they are simply curious about your child's age.