The phrase "age spectrum" refers to a range or continuum of different ages. It implies that there are people of various ages included in a certain context or group. Full definition
At a guess, it's geared towards the younger end of the gaming age spectrum, but my daughter and I absolutely loved playing it. (ab-gaming.com)
A college student and a senior citizen are at opposite ends of the adult age spectrum, yet both have some things in common. (rentersinsurance.net)
Unlike doctors and architects, who range over the entire age spectrum, postdocs are overwhelmingly in the healthy prime of their lives. (sciencemag.org)