It looks pretty good. It's very reminiscent of the Song of Ice and Fire covers
I know you're not meant to judge a book by it's cover- but can certainly tell it's a fantasy book
I hope you don't mind me providing some feedback- it's all more composition based than anything else- the artwork is very good.
I think it currently works well as a single image, but the red border might look strange translated into 3D- I think there should be a red border along the left hand edge of the Front cover, as having one side green might look a bit unbalanced when folded. I'd also try to align the text more centrally, your name is a bit too much to the left and out of line with the title. It also might work better to drop the title a bit lower, I think its getting a little bit lost so high up, bringing it down might make it more eye-catching
Also, unless it's a very thin book- I'm not sure where the spine is? iI currently looks like the barcode might have crept onto it a bit, so it could be moved lower and more to the left
. I also think a serif font, like Times New Roman, in black might work better for the back, the cartoony white text looks a little bit like it's a childrens' book.
I hope I've not been too nit-picky, it's a great attempt