A level psychology has often been chosen by students in the past who have mistakenly believed it to be an easy option and the easiest of the sciences. This, however depends on what you enjoy. If you enjoy wondering why people do what they do, what motivates us, why a person might risk their life to save another whom they have never met, and yet why 18 people can walk past a little Chinese girl as she lies dying in the street, then you will find a lot of this subject easy. Other parts you will find hard; if it were not difficult it would not fascinate so many of us for so long.
You may need to start understanding philosophy of science, how to work ethically with human subject in your experiments as well as learning a lot of history of the subject. You will need to develop an analytical and critical way of thinking about scientific experiment and proof and you will find yourself beginning to question a lot of the science that you hear about in the popular press and asking questions such as 'who funded that research?', 'is that really what that experiment shows?'
This is not the easy option at A level, and in fact it can be one of the most difficult A levels as you need to have both a scientific and an artistic approach.