Q: Boot Camp: not enough space on disk

I just got a 13" MacBook Air with 128GB hard drive space and I tried to use boot camp to create a partition for windows 10. I kept getting the error that there was not enough space on the disk for windows 10, so I called apple support and they said I needed 55GB for windows 10 so a 60GB partition would be cutting it too close. So I took the computer back to the store and exchanged it for a 256GB version so I could make a 128GB partition. But now I am still getting the same error. Can anyone help?