You've been dating a guy for 3 months. He's 30 years old. It's going great, he has his own place, great job (whatever that means to you creative or monetarily), looks good etc. etc. Up until this stage, he's your ideal partner.

You find out that the girl he "dated" directly before you was 18 and she had just finished high school. He says it wasn't serious because she's too young.

He wants to be serious with you because you're closer to his age and are at a similar point in life as him.

What do you do? Do you care?

It's best that you pretend your age is late 20s/30 for this hypothetical but whatever.