It can also be helpful to think about the ways of studying and working you enjoy, and not just the specific subject content - there are many courses at degree level available that students will have never studied before, so you need to think for those more about whether you specifically enjoy the nature of that course (e.g. if it's essay based or experimental/lab based) as well as generally the subject area.
For example, anthropology is a subject area you won't study before degree level normally, and so you won't have sat exams and had lessons in it before to decide if you want to study it. But you can think about a) whether the types of learning you are engaging in are related to that (e.g. social scientific and humanities type work will be similar to the kinds of things you might do in an anthropology degree) and b) explore that subject through doing some wider reading in your spare time (for anthropology this could be exploring enthnographies, or if you're brave reading some of the theory; for other subjects there may be other things you could do such as science fair work for STEM subjects not offered at A-level).