Nice job on the first one. It is habit forming. Horn is kind of peculiar. If you work it with power tools you can't get it too hot, it smells awful, and it can move around with changes in temperature and humidity. I like it as a knife handle material, personally, but not everyone does. In solid chunks like you did with this one is the better way to use horn. If you cut it into scales for full tang blades it is more likely to have warpage issues. If you drill pin holes, they should be slightly over-size, to try and help prevent splitting. It is, after all, just slightly modified hair, all stuck together in a more or less solid mass.

I might suggest a bit of slimming on the handle to make it a wee bit more comfortable in the sock. Of course some of that comfort depends on how you make the sheath for it as well.

Having fun with it is the best reason to make knives.