Medicine is the obvious one, but it's so majorly competitive and so much hard work would you really want to do it?
I'd suggest a career in engineering, the industry is booming especially for female engineers. Career prospects are amazing and the pay is pretty good too.
If you wanted to stay in education then a science degree like Chemistry, Biology or even Biomedical science would be ideal because it would provide a direct route to a PhD. If you're a UK citizen then you usually get paid between 16-20k tax free for 3 years before starting an actual job.
The best advice I can give is that you work your damn hardest in your first year of A-levels and if you get those 3-4 A/A*'s then the degree world is at your fingertips.
Hope that helps