I've taken Economics at A Level... And it does require a notion beforehand so that you can understand the more complicated concepts.
I'm taking the Cambridge papers, I don't have the syllabus for Edexcel.
But still, I do have a notion about the subject. My sister studied Commerce, and lemme tell you, Commerce and Economics are not totally similar. Sure, SOME concepts in Commerce will help to understand Eco better, but Eco is more logic, forecasting, politics...
For CIE, answering Economic questions depends more on the country. Like if we, Mauritians use the study guide of Japan, throat cut.
Is your father a teacher? If not, you can take tuitions. Here, I agree with Dude. If you want to take Eco, you have to be really good at it, and find an equally good teacher. Cause it's more complicated than any other subject, frankly speaking.