By far the biggest choices you will have to make as part of your education come, ironically, right at the end. The government states that when you reach the end of your GCSE education your compulsory education is over and you are free to leave.
However whilst this may seem appealing in many cases it is not the best route for you to take, as getting a job with just GCSEs is both challenging and restrictive. There are only so many places you can work without more than just GCSEs and a lot of people trying to get these jobs. By going on to college and choosing to study from a wide range of courses you can dramatically increase the chances of getting work once you finish the course.
College is a very different environment to school. At college you are there because you have chosen to be there, and you will be expected to leave any silly behaviour behind and act in a more mature way. In return you will be given much more freedom. There will be free periods where you can do what you like, however the time is intended for you to study, so if you choose not to you will have to find the time to study in the evenings or weekends. However, the whole system is set up to make you realise that the benefits of getting older also mean you have to think and plan for yourself.