Late teens/early 20s. Once a girl's hips have finished widening, it's when she is good to go.
Biologically speaking, of course. Getting teen preggo is a bad idea for a variety of other reasons (interferes with school work, too immature to actually take good care of the kid, makes it harder to find employment, etc.) >>100711712>>100711712
But can can she still morph into her sexy half-monster form? >>100709470>>100709534
Sorry she can't be a fat niggerlipped ape like your gay rock show, some of us prefer actually attractive waifus.