I was a student on an aerospace engineering course a couple of years ago and as far as your question about mathematics goes i found that these types of courses are usually designed with the idea that you already have a solid knowledge of mathematics and physics or at least a basic knowledge. Im not saying you cant succeed but in my experience those who were not particularly strong at mathematics and physics were left behind and ended up either dropping out of the course early or hanging on until the end and failing.
As i said im not saying that the above applies to you but it certainly helps if you have a basic knowledge of these kind of academic areas. You will most likely be on the course with those who have studied mathematics and physics at A level to a high standard.
Best of luck whatever you decide