Ironically i do those exact a levels. They are extremely challenging, I took them to do Law though, which is a challenging subject on a whole. I do believe if you want to persue a career in Psychology then taking psychology is fine but I would suggest also taking biology? There is alot of biology in psychology and although i have learnt to understand, I am aware that this biological aspect increases in university. Nevertheless, biology is an extremely tricky subject. Extremely.
It is up to you but do think carefully about it.