AS-maths is very generous compared to the second year. It's certainly doable but compared to year 1 I found it much more... challenging? It's hard to explain but I personally found A2 maths harder than AS-Further maths for example so take that how you will.
For context though, maths is very useful for almost any career path and the questions at A-level are very formulaic so with enough practice it is definitely possible to get a B or higher