I did a module relating to artificial intelligence in my computer science course, so I might be able to help.
I haven't done a course fully devoted to artificial intelligence, but from what I have experienced, it's largely highly abstract concepts and a heavy dose of maths. I don't think you'll be heavily disadvantaged if you don't know what computer science is beyond the basics, but I do recommend learning (at least) about the fundamentals of programming and computer systems. It also depends on whether you'll be doing any practical work as well. eg. implementing neural networks. If you are, then learning how to program is a definite requirement. For your first programming language in the context of AI, I highly recommend Python. Learn as much as you can about it along with all its quirks, because it's one of the more popular languages when it comes to deep learning and neural networks - a topic I'm sure will come up in your course. Luckily, we live in an age where there are tonnes of free online resources out there that can teach you pretty much anything you want about CS. If you want to do it the old fashioned way, then just buy an A level book about computer science and read through it over the summer. Hope I helped. If you've got any questions, feel free to ask.