It's pretty good for a first attempt, nice edge.
I agree about grooving the inside of the sheath for the belt loop.
I personally prefer to keep my stitches closer to the edge, usually about an eighth of an inch.
I don't always groove my stitch lines, depends on the look I want and the application.
This one's grooved:
I'll mark my stitch line with dividers, then punch the stitch holes, if I'm gonna groove them, I'll do that before punching.