To expand on my further answer, different schools offer different subjects, eg some schools offer Spanish, others French or German, or even two languages. My elder son had to do a vocational course, whether he wanted to or not, my younger son did not, though the option was there if he wanted to do one. The vocational courses were offered through a local college, which the pupils attend one half day a week, and include things such as beauty and hairdressing, motor mechanics, construction, business. The children of a friend of mine attend a RC High School and they have to do RE as one of their options. As you can see it varies a lot, you'll just have to wait and see what your school offers.
Even then though you may find that you are not able to study all your chosen subjects. This happened to myself at O level, the schools cannot always offer all the children all their ideal subjects so sometimes a compromise has to be made and you have to drop one subject in favour of another one.