I am a 16 year old girl with bad teeth. Can they be fixed? (photo)

I am a 16 year old girl with bad teeth. My teeth are quite straight but my front teeth are very big and my teeth bend in towards my mouth. My smile is also small teeth wise leaving a large unsightly gap between my far in teeth and my lips. I am wondering how I can fix this as I am hoping to have a career in acting and I am very self concious smiling. I do not have any money and my parents are not willing to pay anything really towards any part of my life. I was wondering how I could get it on the NHS?