I currently study psychology (as a minor) at Northeastern University London.
You say you’re interested in human mind and behaviour which is exactly the right incentive to start studying psychology. At least for myself, I found myself drawn to psychology so that I could understand myself and the people around me better. It’s a social science, so it does explain social issues in a scientific manner which helps to de-mystify the mind/ psyche.
If I may ask, have you considered a further career in this field? A lot of people choose their subject based solely on interest so don’t worry if not.
As for good universities, of course I’m bias because I go there but Northeastern London offers BA (Hons) Psychology, and as well as the university being in small and student-centred in central London, the course offers you opportunity to study abroad at the much bigger American campuses too in Boston and New York (which I think is a great opportunity). Other good universities I can think of are UCL and Birbeck.
Also, do you have any particular interests in the field psychology?