I see what you mean, yeah. We do use similar proportions. Though I did draw Cirno purposefully with a childish appearance, older girls would have a leaner build. (Cirno's over 60 years old, I know. She still looks like a child.)
And don't worry, I've seen far more extreme stuff. A bunch of girls in diapers won't faze me.
And it's good to see some attention from Reddit. It was a bit disheartening to see this get so little attention compared to my quick doodles. I was already expecting my random art shares to get more attention, as they are by artists far better than me. But for a piece I worked months on to not get half the attention of doodles I made in minutes? It's crushing.