When I added Bindi to Bam-Bam's life after Pebbles died ( lymphoma at 1 1/2 years old), I didn't realize, at the time, that Bam-bam was a
girl.so I did end up mixing girl/girl...of course, at the time I didn't know Bindi was a girl either. I just wanted them to be friends!
It took about a month total for Bam-Bam to accept Bindi...we started off in separate cages for about 2 weeks but when I tried putting them together, Bam-Bam was quite the bully and Bindi was on the bottom perch too much and Bam=Bam took a nice piece out of her beak, too. So they got separated again but what REALLY worked was moving Bam-Bam OUT of the original cage into a new one and letting Bindi have that cage....got rid of the territoriality issue right away and made it easier to help them along.
Now I know I've got two girls and they are totally, madly and deeply crazy about each other.....it's quite ridiculous. I have a bonded pair of female lovebirds who act as if sex is the only thing worth doing...hmm....thought that was a guy thing!!!