I've been mapping for a couple years now, and developing skills over time.
You can't just leap into a large-scale project and expect things to be easy. That's experience talking there. I started on a mini-mod type thing myself, fairly early into my mapping time. I didn't even start mapping for it because I KNEW my mapping skills needed much more improvement before a could do it. But I got what I could do done (which was mostly customization) and it's been laying dormant for about a year now. I add one or two things every now and then.
When I'm certain of my mapping skills and I've made a few good maps, then I'll see what I can do. Until then, it shall lie, waiting to be rediscovered...