please help with my a-level choices !!

A-level maths is extremely formulaic. Every question is basically a repeat of a past paper question with different values so if keep up with everything and regularly do practice questions you will get a good grade. It's a bit of a leap but to be honest it's completely doable and I wouldn't say its that bad as long as your prepared to take it seriously and put in work.

It's only about practising a lot, if you do enough work it would be relatively easy to keep up and get good grades, for maths I'd say that the workload is more and the deeper understanding of the concepts + practice for fast recall is what makes the difference between students, economics is also about practise and most students who take it did think it had a lot of maths when it's actually an essay based subjects (My mistake) where you talk about things like Government intervention in market, Economic growth of a country or Market structure, demand supply etc. It's more of "how the economic system work" than the financial aspect of it even though you still have some formulas and lots of graphs. But it's really doable especially if you are able to get 9s at gcse, you will be able to do it.
But if you care about the maths, you might want to have a look at the differences between Economics A and Economics B if you are taking edexcell, people say that econ B has more maths, Im doing A

Hi, I'm applying to college in September and considering studying economics, maths and Spanish. I wondered if anyone has any tips or anything to say about the courses. I'm currently predicted 9s for both maths and Spanish but I have no prior knowledge of economics. Is the leap from GCSE maths to A Level as bad as everyone says?? I'm fine with Spanish since I speak Portuguese but if anyone has any advice on economics it would be greatly appreciated haha

A level Maths ain't difficult. If you have taken further maths for GCSE, it will greatly aid your A level maths. If not taken FM, no fear as A level maths ain't a killer, just keep practising. If you are going into Econ, FM will help but not all people take it.
Sorry can't say about the rest of your chosen subjects as I am taking Chemistry, Biology, Physics and Maths
Ace your yr12 n you will be fine.