What's your experience with Psychology so far?Watch
My biggest advice when choosing a psychology degree would be to look at the exact modules each uni do and to choose the ones that sound most interesting to you, as there is quite a bit of variety within the modules each uni teaches.
Edit : Sorry just realised this was about A-Levels
During my A-Level (Edexcel), we covered mainly: obedience, prejudice, cognition (memory theories and dementia or dyslexia), the Biological Approach (brain damage, evolutionary theory of aggression, Freud's Psychodynamic theory and hormones), learning theories (classical & operant conditoning plus social learning theories) and Health Psychology (drugs).
If any of this sounds interesting then I would definitely give it a go in Year 12, however be prepared to memorize and regurgitate large volumes of information (things like definitions, explanations and STUDIES). If you do pick it, then I would strongly recommend you do active recall from the start of the year by utilizing flashcards, as that is probably the most effective way to memorize large volumes of info.
Regarding the maths, all it is really is just some simple statistical inference testing. If you happen to be doing A-Level Maths then it should be a breeze.
I never studied Psychology at A level so I was really anxious when I started my degree that it wasn't a subject I would enjoy or be any good at. Luckily I didn't need to be concerned about either of those things! Psychology is such a broad subject that encompasses so many areas but some of the general areas we've looked at across my time at university includes memory, development, aggression, neuroscience, computational psychology, emotion, criminal psychology, sleep.
I can assume A level will touch on all of these areas in less detail, so if that's something you're interested in I'd heavily recommend it! It's very essay based at degree level so that's probably something look out for if you don't enjoy being assessed in that way.
If you want to learn more about psychology I'd recommend this series on Youtube: https://www.youtube.com/watch?v=vo4p...H9KVU6&index=2
SciShow and stuff like this what introduced me to the subject and now I'm pursuing a career in the area!
Some other advice if you're looking to go further with the subject after A level (assuming you take and enjoy it) is don't be afraid of statistics! A lot of people who approach Psychology and a question that gets asked at open days a lot are about the level of maths ability you need. My course eased us into statistics and using programs like SPSS slowly and it was (strangely) really interesting. This isn't really applicable to you yet, but in case you decide you want to pursue a degree in Psychology like I did.
Good luck It's a great subject.