Crashing Advanced Higher Economics?

My plan is to go into Economics, and I'm taking Maths, Statistics (maybe), and CompSci to Advanced Higher Level. However, I never took Economics to higher in S5 because our school doesn't offer it to AH. I just heard that a nearby school is offering it this year, so I could maybe go there to study it. However, I've never studied economics formally in my life despite having a huge interest in it. My other options for an essay-based subject would be AH Crash Modern Studies (I did N5) or AH Geography (I did higher). What do you think for Economics - my goal is Cambridge or LSE?