How might I handle a co-worker who frequently refers to my age? Details below...?

He constantly refers to me as "ppl your age" and to other coworkers as "ppl my age." I am not his supervisor and we have the same amount of job experience (same title and we started the same year).
Update: The co-worker is about 10 years younger than I am.
Update 2: I haven't ruled out going to HR but was wondering what I might say to the offending co-worker instead of going to HR right away. Comments from this co-worker have been along the lines of: "What does a person of your age think about this news event?" OR "Why do ppl of your age always do... show more I haven't ruled out going to HR but was wondering what I might say to the offending co-worker instead of going to HR right away. Comments from this co-worker have been along the lines of: "What does a person of your age think about this news event?" OR "Why do ppl of your age always do this...?"
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