Just take your clones now and Kill the ones that turn out to be males!!!
You should always take, from a seeded and needing sexing starter crop, at very least one but preferably 2 or 6 clones from each plant before they flower. It is not only stressful going into bloom and then back to growth but is gonna take that much longer before you have a set of desirable Mothers.
When you take the clones mark them all to their donor. Also mark any that display a trait that you Like OR Dislike as the clones that you take will display almost identical characteristics like growth, tightness of nodes, and so on, as the plant it was taken from.