Hey man, don't be surprised by their short height. I have the same thing with my F.B. Cherry; it’s totally normal 👍 (I'd recommend pruning the leaves that point inward toward the main stem).
Hey man, plants are looking great! Fingers crossed for the grow. If I may suggest one little thing—I'd take that scrog net off for now. The plants are still small and the net is casting shadows; it’s only slight, but why lose out on any light unnecessarily? 🙂🍀 Happy growing !🍀✌️