Hi Mentors,
I am confused about these two sentences.
We are of the same age.
We are at the same age.
Which one is correct? Please help me.
Thank you so much. 
More usual than either of these is “We are the same age”.
“of” is possible but not very conversational. To me it sounds formal or even old-fashioned.
“at” is possible but not particularly common. It seems to have a particular nuance, as if it implies that we both behave in a particular way because of our similar ages, or are at similar stages in our careers, or something like that.
Ahhh I see! Thank you so much Sir.
How about this one…
Here are the boys of/at/with the same age.
More context is needed. In what situation do you want to say this?
For example, there is an activity at school then I am going to introduce to the other pupils that those boys on the stage are at/of/with the same age.
Those/these boys are of the same age.