So much of the magic done here is a reflection of experience using the tool. I find the best way to get experience is through doing it. Following a few tutorials can net you years of experience in your tool of choice because they won't teach you how to remove red-eye from a photo or how to create a fairy in a forest, leaving you to apply your own context. Welcome to the guild my friend and my your journey of discovery be as fascinating as mine has been.

The map you're building is insanely cool. Now I want to DM just to do something massively fun like that.

PS: I'm more like you... I fell in love with maps in 1977 after reading The Hobbit. My life changed that summer. Between Tolkein and Star Wars, it was just more than a 14-year-old could process.