I heard that you can tell a guppy is ready because they go square. Is this what that means?
I haven't heard that, my guppies get really round actually. I think yours still have some time, or it could just be a small batch.
A guppy female that is almost due, can be round bellied or squared off. If one is squared off, it means that she's used her max gestation period 9the max gestation period differs per guppy female). Nothing more. The size of a round belly or a squared off belly is irrelevant. For the size only tells that she's got a lot of embryos, a low number of embryos, small embryos or large embryos. Nothing more...