Welcome! You're very lucky to have realised its not the truth at 16. You're finished with childhood and almost ready to begin your life. My sister left at 16. It was a tough time for her and my parents but she never looked back and, as she was never baptised, she was never shunned. Now she's the happiest, most successful member of the family. She started to fade from meetings using her exams as an excuse. She needed to revise.
Ive made an assumption from your post that you are female and British, same as me. I'm going to give you the advice I wish I could give my 16 year old self....
Don't waste too much time on here long-term researching, obsessing about witness land, just do what you need to do to convince yourself you're doing the right thing, get support and move on. Believe me, the more you step back from the religion, the crazier it all seems. You won't need reminding! I do think you should get a copy of Combatting Cult Mind Cintrol though. I'm reading it now and it's so helpful to see that there are so many other cults that operate the same as the JWs and their followers believe they have 'the truth'.
forget about boys, drinking etc, there's plenty of time for that. Concentrate on your studies, that's what's going to get you where you need to be in life. Don't give your parents more reason to worry. Make them see you're intelligent, sensible, not going off the rails and capable of making your own decisions in life.
Don't completely resent your upbringing. Your parents did what they thought was best for you, they love you and have given you a good set of morals that can serve you well.
Personally I'd forget about the gap year and get straight into uni. The way the system is designed in the uk, it doesn't help you to have savings instead of getting a student loan. You've got 2 years to prepare yourself and your parents.
Uni is the best thing you can do for yourself. Dont believe the JW stories that uni graduates don't get jobs. All my friends now are 30 something uni graduates and have very good jobs, own their own houses, have comfortable lives on top of the extra life experience and friends they gained at uni.
maybe have a proper sit down talk with your parents (only you know how they will take this though) and let them know that you don't want to be a JW and will go to the meetings while you live under their roof if they insist but it's not what you will be doing long-term.
pgood luck!