when did you realize that you were Gay/Bi?

I know that Gay and Bi aren't the only sexual orientation but you got it what i asked, also i know that this is a frequent question. Anyway i have this question for you all. Everyone that i know telling me about they realized his sexual orientation about his 12-18 years old (i am 19) or they tell that they've alway known it. So i wonder and ask the title, By the way if you want to tell extra info. That's better. For example : your first bf or something like that.