Is it normal that i always think about being taken advantage of sexually? +more

Ok, so I actually have more than one question. 1] Is it normal that I think of sex all the time? I am an 18 year old female, and I swear about 70% of the day some sexual fantasy is running through my mind. Society doesn't make it seem as if girls think of sex that much... I'll see a guy with big arms and I'll imagine him picking me up (my thighs on his forearms) and us just having sex like that. I'll see a guy with nice abs and I'd automatically try to picture his penis. I'll even see a cute girl with a nice body and envision her eating me out. 2] Does that make me Bi? That I fantasize about girls doing things to me? I didn't think so at first because I could NEVER imagine myself going near another girl's vajayjay. But then again I would gladly let her be all up in mine so now I'm a tad bit confused. And this is only sexually; I don't think I'd actually date a girl. 3] When I think of sex, I just want someone to put me in different positions, and do whatever they want to me as long as it isn't too painful. Is that normal? Or is that me just being lazy? I probably should mention that I'm scared I'm not good at sex, so maybe that's it? I don't think I'm good so I just let them take advantage instead of me embarrassing myself? Comment please! I'm a bit self-conscious, I don't show it, but I often think it. And if you don't mind, could you put your age with your comment? Thanks!