You should rest assured that economics has been deemed a subject entailing concepts that have been interrelated. It would imply that one chapter has been built on the previous chapter that has been built upon the chapter read or gone through earlier.
Therefore, it would be in your best interest to start economics tuition and begin preparing for the A-level economics exam right from the beginning. It would never be too early to get started. If you have started, you should pick up the pace and catch up with the other students. It would be pertinent to mention here that the competition has been increasing with each passing day.