try for work experience anywhere you can that is medical. when i was 16, i was certain i'd be a doctor but then at 18 i changed my mind. i'm still doing a medical degree, but not to become a doctor. be open to the possibilities of other areas of medicine and look into where you can get in for some work experience! i'm on hospital placement myself as part of my degree and it can be very hard to fit additional students in, especially when they aren't able to contribute in any way - so don't feel disheartened! particularly when you're under 18, you quite possibly won't get a whole week in a hospital as there's nothing you're allowed to do and they have to fit you around them. but you'll get something eventually.