Wow, I'm surprised at all the people saying go for it. I'm 5'10", been riding for about 12 years, and I definitely would not recommend the f800gs as a first bike. Low speed maneuvering, probably the hardest part of learning to ride, is more difficult due to the height of the bike, regardless of your size. Not being able to get both feet on the ground contributes to that at a stop (and confidence in general), but otherwise the rider's height isn't a huge issue.
Something I didn't see mentioned is braking. Braking hard on the f800gs, the front end wants to dive significantly. This eliminates any control you have. With experience and technique you'll to brake properly, making the bike "sit" rather than roll forward. In high-stress situations, having a bike the is more forgiving for a noob will keep you alive.
Could you get one of these bikes and do fine on it? Sure. But is it a good idea to risk your life over it? Not in my opinion. Grab a cheap, more forgiving "standard" style bike and ride it for at least a full year. You'll learn a lot and likely be able to sell the bike at about the same price you bought it. Or a small dirt bike... but I find it's more the road that you have to worry about, as people ignore traffic rules and don't pay much attention when driving.