That is what I heard as well. I will add that the tradition states that Maha Pajapati (Buddha's step mother/aunt) and Ananda (1st cousin/close disciple) had to

That is what I heard as well. I will add that the tradition states that Maha Pajapati (Buddha's step mother/aunt) and Ananda (1st cousin/close disciple) had to convince Buddha that a female order was viable, so this argument goes all the way back to the start. There are nuns in the Zen (Mahayana tradition), so I don't think the line died out through China (not sure it is unbroken though).