Macbook question.

I know I should go to a Apple store, but I was wondering if maybe someone on here could give me a little advice. So I am going to start school in a few months for Accounting. I want a Macbook computer. I want something smaller and light. I was considering the Air over the Macbook. I would only be using it for school, saving docs on the computer, internet surfing, and using the iWorks for my current job, which would not require much use. I was looking at the 13in, which has 128gb if I remember correct. So my question to all you computer people is, should the Air work okay for me? Or should I go for a Macbook? I do not ind having a external storage in my bag to carry around. Thanks for the help.