Hey,
During Psychology at A-level, I can promise you that the maths is basic. It's not the standard algebra, multiplication etc nor is it quadratic equations. You will start using a statistical programme called "SPSS." When you get taught how to use it, it's fantastic. Every experimental psychologist out there uses this programme to analyse data and provide accurate results. But, it's not overly difficult once you know how. SPSS is not used a lot at A-level, but if you plan on taking this subject to degree level, you will find you'll use it a lot more. It's fun, I promise! And for the records, I achieved a C grade at GCSE level.
Sociology is another essay writing subject I'm afraid however, if you choose to take any social science subject, you'll find it hard to move away from this. Developing your essay writing skills is crucial if you choose to go to University but it all depends on what type of person you are. Are you more facts and figures or do you prefer to think outside the box, explore theories and debate etc? If you prefer a more black and white, straight cut subject then psychology and sociology may not be the best option. Economics and any hard science like Biology is more like it. Psychology is tough at times because you have to argue points from many angles and theories; there's a lot of information to process and it can get a tad confusing. Saying this, it still remains my favourite subject (probably because I enjoy thinking critically; like debating topics and don't see things as being black or white).
The only piece of advice I can really give you is to choose your subjects wisely; don't choose Economics over Psychology because you hate writing lots of essays or don't choose Sociology of Psychology because you're not overly mathematical. Make sure you choose the subjects that will aid you in the future but also those that you enjoy. If you plan on going to University after college, then remember it's exceptionally competitive now; you will want to give yourself the best possible chance.
Above all, enjoy it!!
Ash