Do you have a default assumption for other Flutherites' age before you really know?

When I was younger especially my “default” was assuming everyone I saw online was my own age. They were however old I was, till proven otherwise. Occasionally I still find myself doing this. It’s less pronounced, but sometimes I am surprised for a moment when people mention something very age-specific (like being in high school or being retired) that is not consistent with being 20–30.

Does anyone else do this? Do you have other baseline assumptions, or make no assumptions without some kind of proof? I try not to, but for some reason there’s this gender-neutral twenty-something figure which acts as the default for a username I’m not familiar with yet.