I'd say go with Blender 2.8 first.
2.8 is easier to learn, and has a lot of tutorials. Focus mostly on how to create meshes and do UV unwrapping and basic texturing. Don't bother with things like particles, armatures or material setup with nodes - those won't work with Korman, and you can learn them later anyway. Creating meshes and mapping textures on top of them is what's important when creating an Age, even though it's only 15% of what Blender can do. And while the interface/shortcuts are different, the process of creating complex meshes from scratch will carry over to 2.79.
Once you're comfortable with the basics of 2.8 and have made a small practice Age, backport it to 2.79 (it's easier to export/import to/from the FBX format, since both versions of Blender understand it really well). Start figuring out the differences between both Blender versions - should be easier since you're already familiar with 2.8. And then learn how to setup things with Korman in order to export to Uru. The Wiki here has plenty of tutorials to help you.
Personally I used a lot both versions of Blender. I'm faster and more comfortable with 2.79, so I mainly use this one. But I know 2.8 is better if you plan to export to a more modern engine like Unreal/Unity as the lighting and material editor is more similar to those ones.
Keep in mind that the most important thing is to have fun. Motivation is what allows you to create a whole Age without getting bored halfway through. But before building can become fun, you have to get comfortable with the software itself. And that involves learning. Start slowly by creating a very small Age - usually an interior location with some furniture. Try putting it in the game. Once you've done it and are satisfied with the results, try doing something slightly bigger - maybe a few more rooms, more interesting architecture, a few plants. Test it again ingame. Then try doing an interior location with a balcony overlooking a small garden. Then try to make a slightly bigger garden. Etc. Don't go rebuilding Ae'gura right from the start, otherwise you're going to fail. You're going to run into a lot of challenges, so it's best to start small and tackle them one at a time. Eventually things that were hard at first will become natural and easy.
Also: focus on doing the things you enjoy the most. If creating plants annoys you, focus on architecture. If texturing annoys you, focus on lighting. If lighting annoys you, focus on making fun locations. We have Ages that aren't pretty, but are really fun to explore. We have Ages that are extremely small but good looking. People love exploring both.
Heck, even if using 2.79/Korman/Uru annoys you, you can still switch to another game engine. You'll lose the multiplayer component, but gain better materials and lighting.
Oh, and don't hesitate asking for help here. We don't have all the answers, but can help troubleshoot, provide some tips, feedback, etc.