When I shop for a new computer, I always consider what I’m trying to get out of it. I have used both Apple and Windows systems and I’m comfortable with both but for different reasons.
If you’re going to be using it for school then you have to consider if there is any specific software you need for your classes that are only supported by one OS or the other. When I was taking geoscience classes I found that most of the software was built for Windows and there was little Apple support so I purchased a Windows laptop.
If software isn’t a big issue and storage is your only consideration, keep in mind that with a Google account you can store papers on Google Drive; which I recommend anyway, which frees up storage space and allows you to access your files from any computer connected to the internet.
Lastly, since you already have a MacBook Air and if it’s in good working condition then having an alternate system isn’t always a bad thing. It really comes down to what feel you need to get out of the new computer and what you are comfortable with.
Just my 2 cents.