Noob here - Anyway, its never to early to start thinking about your future especially as you are surely coming to the stage where you will be choosing GCSE’s.
The best subjects to choose at GCSE are ones that you feel comfortable with, that will act as a stepping stone to take you onto A levels.
Focus on the strong foundation subjects like maths, science, English and also start thinking about the skills you want or need to develop to become a successful lawyer. History for me was very beneficial in developing analytical techniques.
When it comes to A level you will be able to narrow your options obviously. This however is a more important stage as decisions here will impact significantly on later applications for university and training contracts. Pick strong academic subjects. Through personal experience and going through tonnes of advice forums myself when I was a bit older than you, they are a must have. Im talking about English, History, Sciences etc. one’s that challenge you.
It’s a harsh world and is the case, especially when you’re applying to the top universities that certain subjects should be avoided (I don’t need to list them).
Also your at the right age to be looking into things like school council, sports etc. building up a good CV that you can carry with you through the rest of your education.
Good luck with your future.