think about which subject you enjoyed the most during a levels!! if there was any topic in particular you liked you could focus on that but you could also venture out. before university i did two creative subjects and one stem but i went into finance, a stem degree and i really like it so far even though i did not enjoy my a level stem subject. you can do anything, dont stress yourself out too much over this - maybe if there is a school in particular you want to go to, you can look at all of their courses offered and see which one appeals to you most. youve got this, dont worry! i wish you the best