I think it all depends on what your girl is like - whats she like around other dogs?? Does she get along with both male and female??? Has she been introduced to puppies before adn if so how does she react?
2 females do get along in the right environment with no problems at all, if you get them both done there will be no hormones flying about when they are a little older.
Female is not always the boss - I really think its down to what Diasy's temperament is ......2 females can get along just like male and female can get along....