the same age vs at the same age

Question

Which one is correct:

1)Unfortunately they are not at the same age so I can't expect them to behave in the same way.

2)Unfortunately they are not the same age so I can't expect them to behave in the same way.

I know that when we only want to talk about people's age we say they're the same age or they're not the same age but what about this sentence,I want to emphasize both about the age and the fact that people behave differently at different ages.

Thank you in advance for your help.

Answer 1

They're both grammatically correct, but to this US English speaker "They are not the same age" sounds much more fluent. "at the same age" does not specifically emphasize that people behave differently at different ages. Also, the phrasing with at is just much less common, so readers are just going to wonder why you're putting it that way.