Really good job, but that's not a katana, at least a japanese katana, they are a little bit more curved in order to deflect their attacks and to be able to be very fast when the person attacks with it. But it looks just great, its just more of a ninja sword instead of a samurai one.
As I had stated in another comment, the blade was originally curved but it just looked silly. So I straightened it out. Technically the sword would be classified as a chokuto, but the average person isn't going to know that. So you're right, it's not a katana, but it's a lot easier to just label it so.