bigcountry is spot on. My personal setup is a 34 ATA and 28" draw. This allows me to put the tip of my nose on the string.

Get that draw length correct first. If you don't, and its too long, you'll give yourself fits. You may find that you need to change your anchor point on your face/chin area to get a comfortable, repeatable anchor.

When I first started setting up my own bows, I learned very quickly that in order to get the most accuracy out of myself and the bow, I needed to find an anchor that worked best for me, then set the bow up. This involved getting the draw length correct first, then finding an anchor I could repeat with the utmost comfort.

Shorten your draw length up first. Now, nock an arrow and point it in a safe direction. Close your eyes and draw the bow. Find a place on your face/chin area that you can nestle your nuckle into comfortably. Keep doing this, shortening or lengthening the draw length until you find what feels comfortable to you and you can repeat. Once you get this, you can then set up your peep and rest of the bow.