A-Level to do software engineering

I did Maths, Chem, Bio, and Physics for my A-Levels last year and I got A,B,B,B not that great, I know, and I applied for Software Engineering at Edinburgh University and I got a place. Since I didn't do computing at A-level but I did it at GCSE and I really enjoyed it.I was wondering if I would have any problem with studying software engineering at Edinburgh because I didn't take computer science, and what I could be doing in order to make it easier as I am aware that people who did computing are at an advantage. Thanks.

The first year of most computing-related degrees tends to repeat a lot of A-Level content - there probably won't be much difference in the first year between Software Engineering compared to plain CompSci. The A-Level computing people will have a nice easy ride in their first year though, you'll probably have a harder time, although your GCSE knowledge should help. Your university aren't going to expect you to know any of that stuff, they will provide you enough material and assignments to help you learn from scratch, but you'll probably have a lot more work to do.

If you want to get a headstart, you could start with this free online course from Harvard, it's a pretty good Comp Sci intro, with a heavy focus on programming. In particular, the problem sets should be more advanced than anything that you'd needed to grapple with at GCSE:
https://www.edx.org/course/cs50s-introduction-computer-science-harvardx-cs50x

I was looking through the course and some of it I understood but others it was difficult....is this similar to what is being taught at uni??

Yes, very much so - A-level computer science would also cover nearly all the same things as CS50x too. Remember the core of it is all about trying to 'think' computationally; so it's not supposed to go too far in depth on big topics like cryptography. Most of it is about examining some well-known problems and learning to think about how to solve them. Another part is getting a better understanding of some much lower-level programming concepts than you'd have seen in Python at GCSE.

You're almost certainly going to need to understand the C language at university, so things like memory and pointers in C are a really important topic, and so are the various data structures which use them. Almost everybody finds the concept of pointers really difficult to understand at first, so if that seemed too difficult or you had a hard time with any data structures - don't worry, everyone else feels the same, these are very "alien" concepts for most people.