My DD2 (11 soon to be 12) came out to me and DH in June as bi. I had a similar conversation with her as you did mmsmom. It was of course Pride Month and she wanted alllllll the pride things from Target. She wanted to buy the bisexual pride flag for her room and I happily supported it. She told a bunch of her 5th grade girl friends and even told one particular girl that she liked her. That girl liked her back. For a week. And then that ended (as most 5th grade "relationships" do!). I did remind DD2 that her friends and their parents may not talk about sexual orientation and gender identity the way that we do in our home and to be cautious about what she discusses with her friends but to also let her friends know that we are supportive (in case any of them need support they can't find at home). She was very very prideful and expressive of this new label for a few weeks but honestly hasn't mentioned it since. Is it a phase? Perhaps. But I'm happy to encourage and support her exploration of herself and her identity. No one bats an eye at a child/teen/tween exploring their heterosexual and cis gender identify at this age. First kiss, holding hands, crushes, fleeting moments of "dating" in middle school are really quite common place and so if my kid is exploring those things through a bisexual lens, great. Maybe that's who she will be forever, or maybe not, but I don't seem harm in it so long as she feels accepted and happy in that exploration.
Mom to two amazing DDs ('07 & '09) and a fur baby.
Gluten free since Nov '11 after non-celiac gluten sensitive diagnosis. Have had great improvement or total elimination of: migraines, bloating/distention, heartburn, cystic acne, canker sores, bleeding gums, eczema on elbows, dry skin and scalp, muscle cramps, PMS, hair loss, heart palpitations, fatigue. I'm amazed.