Technically, I was 12 or 13. I said one day to my mum, I think I like women in that way. She then said that sometimes when we admire someone, especially older, it can feel like that- I felt brushed off and never mentioned it again until a few years ago.
I knew when I was about 7 that I liked my teacher, and used to write her little love notes, but to me it almost felt motherly- I'm an only child and I used to write my mum little cards saying 'I love you'. When I was a teenager I struggled with my sexuality so much- I thought, I like women, so I must be gay, but I also had a massive crush on my male teacher, and liked celebrities, so I must be straight, but I can't be both- felt like I was going to combust trying to work it out! I was pretty much in love with my best friend at school and had a huge crush on another female friend in college but I don't think I recognised that I was bi, I just thought I was weird and that something was wrong with me.
My first serious boyfriend/partner did not approve of women having relationships/sex with other women, and used to make comments about it, so I tried not to think about it; I was with him so I shouldn't be thinking about other people.
Then we broke up, I had a few dates but nothing serious, and experiences with a woman. I said to my mum 'I'vegotsomethingtotellyouIlikewomeninthatwayaswellasmenlet'sneverspeakofthisagain' and ran out of the room, I was so scared what she'd say. She looked thoughtful then said 'Does that mean you're going to be promiscuous?' really seriously. After I stopped laughing I explained that it doesn't!
Then I had a relationship for a while with a female friend of mine, not exclusive as she had a bf in an open relationship. Then I met my current ex, a male, and fell in love with him, and he understands that I'm attracted to women, and doesn't/didn't make me feel that it was wrong in any way. I like to say that I like/love the person, it doesn't matter to me whether they're male/female/transgender/something else; I feel incapable of ruling out love or sexual desire based on genitals or gender perception.
I always feel slightly odd saying I'm bi when I'm involved with or like a man- as if I expect myself to have both a bf and a gf, but when I'm in love with someone I'm monogamous, that's just how my feelings have so far dictated in relationships.