IMO an important aspect of a beginner bike for a woman (assuming average size/strength - i.e. somewhat below men's) is low weight / seat / COG.
Because it'll be a lot of minor mistakes and non-appropriate moves at lowish speed, that will cause a beginner to drop a bike. (Stalling a U-turn, hitting the front brake too hard, loosing footing/balance etc. - think we all know them!)
Like learning any new motor skill, your body will with practice learn to make these less frequent, and be better at correcting/catching the consequences a split second earlier. Thus making taller/heavier bikes a good option only with some experience.
Continuing with the stereotypes, women propably less likely than males to twist the throttle 'in anger'. So don't think 50 or 70 or 100 hp will actually be too important... (Oh, but maybe a non-faired bike could help keep outright speed in check, if that's a concern!)