Am I straight, , or bi?

I am 15, and I am not as interested in guys as I used to be. My last crush on a guy was when I was 13. I still find some guys hot i guess, but I'm not emotionally attracted to them anymore, and I'm not as physically attracted to them as I used to be either. My first "girl crush" was last year. Accept it wasn't on anyone my age, it was on a teacher of mine who was in her mid-late 30's or early to mid 40s. Although I thought she was really pretty, and I was kinda physically attracted to her, what really made me like her was her personality. I was always so happy whenever I was with her, she was so funny, and nice, and I thought I might have loved her. At first when I thought about kissing her it grossed me out because I guess I knew it wasn't normal for me to think about kissing a girl, but then I sorta got used to it This year I've liked two more girl teachers. I had no issue thinking of kissing them, and one of them I'm more physically attracted to than the other, and the other one, even though she wasn't as pretty, when I liked her I thought she was, because I was really emotionally attracted to her. I really don't wanna be a or bi because I know it will cause many issues in my life. I really want kids that are biologically mine, and I want them to have a mother AND a father. I don't want them to be teased for having not straight parents, and I don't want my parents to be upset with me for not being straight. As much as I really want to be accepted, and have my kids have a normal life, I want to be able to have a normal life too. But the other issue is that I want to be with someone who I love, and who makes me happy. Im sorry that this question is so long but Im just sooo confused! Am I , straight, or bi? ... (If I'm bi should I just ignore all my girl crushes/girls that I'm in love with until I fall for a guy?), and what do I do about falling in love with all these older women. Can anyone tell me why they think I keep liking people who are more than twice my age? THANKSS SOO MUCH FOR ALL YOUR HELP!