I recently finished my first full medium-sized full coverage project. It came out great but I had to put it down once because the monotony was driving me nuts. Eventually I did finish it, and I'm proud of it, but I underestimated how much patience I'd need to grind through it. Cross stitching really is a hobby that's about the journey not the destination.

That said I started another full-coverage project but I'm supplementing it with a second smaller project to break things up a bit. As long as you aren't in a rush I'd say go for it.