Just a few words: Older. Sister. With. No. Respect. For. My. Age.
She'd tell me everything, and I mean everything. She came out about being bi when I was twelve, and told me about the time she fell out of the bed while doing it. Do you know how much that screws you up?! (I'll give you a hint: I have pictures of Shadow the Hedgehog next to my bed.) Your sister says she likes to do both genders meanwhile you don't even understand what 'doing it' means, and you just get confused. And then barely a month later, she tell you another story. I tell you, I was the only one in my grade 7 class who could accurately define 'Cunnilingus'.