Struggling with confidence

Why is life so hard? Why does every day have to be difficult? Why can't I just be like any other normal girl of my age? I feel that every day there is some reminder that I am a totally inadequate excuse for a woman. I am the opposite of the definition of a woman. Why? I lack confidence. Where can I get it from? I wish I knew. I spent my gap year volunteering with elderly people and I loved it. I can talk to them. I used to be really shy around them but now I am confident around them. I know what to talk to them about and can hold proper conversations with them. I know how to get on with them. They like me. So why can't I be that confident around people my own age? Only God knows. I went to an all girls school and I am fine around girls. But guys...that's a whole other story. I am so shy around them and never know what to talk to them about. I can talk to gay men perfectly fine. But straight ones. I come over all shy and awkward and I get lost and just fade into the background. Lost amongst all the other loud, confident outgoing girls. Somtimes I say something and people don't even hear me. That's what happened to me today. I struggle to get noticed. When I am in my tutorials, I am fine. I can talk about anatomy and impress my tutor and stun everyone else in my group into silence perfectly fine. They stop and notice me and it feels so good. But social siuations are very different. It's not like I speak quietly but I am easily just part of the furniture. why can't I be more confident? Why can't I be different? What on earth can I do to change things. It always takes me a while to become settled into a setting and then I am okay. But by then it is usually too late. I am 20. How on earth am I supposed to be the kind of girl that guys want? How on earth am I supposed to meet someone and fall in love when I can't even look at a guy I like without blushing or going all coy. It's a disaster. Will confidence come with experience? Will I slowly learn to become more sociable and outgoing? Who knows.