I don't mean for my comment to be negative towards you but it's probably come out that way.. my experience can only advocate for your child, as I was a queer kid.

This whole post is about you, and it's valid to feel all of this! just know it's not your childs responsibility to deal with your feelings... Def sort this out with a therapist. This moment is about your kid.

Also coming out at bi at a young age isn't that outrageous. Everyone assumes their child is straight and make jokes as early as toddler hood about being a "heart breaker" and what not... 11 is about the age I came out. And IF it is a " phase " (A very small percentage transition back / feel differently , or change more their identity later) the more support you give them now, the better they will feel about coming to you when they are vulnerable.

This is still your child. This is an opportunity to gain, it makes me sad when people describe thier queer child as grieving the loss of their normal straight one...