Looking for advice on access maths online (nat 5 level) course at Aberdeen Uni

Hi i am thinking of taking the Aberdeen access national 5 maths course. I am terrible at maths but i need it to get in to social work. How difficult is this course? Are the learning materials easy to understand? What topics are covered? I was considering doing nat 5 applications of maths at college this year. I don't know if that would be easier or not. Now my local college are not sure if they will be running the applications of maths course. The accesss maths online course appeals to me because you can do the exam at home and study at your own pace. I was having a go at some of the bitesize maths and finding it difficult, but it didn't offer a very full explanation. I did standard grade maths and got a 3 in 2007. I studied highers at college in 2018 and got a C in human biology though and that had some maths / problem solving type questions. Maths is my weakest subject. I really need this to get in to uni but don't want to pay £100 and set myself up to fail....