[Okay, so she's not really thirty feet (more like thirteen), but she certainly feels massive sometimes. In Yagyuu's estimation. Especially when she and her boyfriend attempt to cram themselves into the neighbor's pool, good lord.]

Smaller, but similar-looking, yes. Thalassa was just under two meters long when she hatched — [Oh, right, she probably has no idea what the metric system is, huh.] — that is, about half the size she is right now. They grow considerably as they mature.