Medium should be fine. You will be at the upper end of its size range as you noted. Yeti's size charts are pretty accurate;so a lot will depend on your particular riding style.

If your style is toward the aggressive side, a medium will center you in the cockpit better. If you are more XC-oriented, you may want to be a bit stretched out; but I would still peg a large at a 6'-0" or taller rider. I rode a medium AS-X for almost all my riding (except XC races) and I am 6'-1".