I don't think he was trying to hit on me or anything like that. I just don't get where it was coming from. Like, the dude is talking to me as if I'm a school age child, so that's somewhat insulting already. Is he just making light of me being much younger than most of the others in the office? Is there something more sinister? Is he picturing me in a little plaid skirt? Is he imagining telling me to stay after school for a "special detention"? I really don't know. I'm just not sure what to make of this.
30 is a lot. If he didn't have kids, maybe he was trying to figure a way to relate to you? When I was working, I was in an office with a lot of girls, most of whom were twenty years younger than I was. There's an old philosophy of male/female interaction which says men can treat women in one of three ways; potential dating material, maternal types (older women, aunts, mothers) or sisters. I chose the last for obvious reasons. And several of the women I met back then, going on eighteen years ago, are still kind of like my sisters. But in most cases it was me who interacted with them initially. In at least two cases, they thought I was weird at first (they have since confessed). They weren't really used to interacting with people my age either, except as parental figures, teachers or bosses. And they sort of expected me to act very stern, and official and businesslike, rather than joking around or teasing them.