The picture could be effecting this but... It looks like you are not holding the string in the middle of the bow e.g. the upper portion of the string is "shorter" and the lower portion is "longer." You want to be careful to pull the string in the same location that you pulled it while you tillered the bow, so as not to cuase uneven stress on the limbs, and increase set.
Again, great work on your first bow. I'm looking foward to seeing more of your work.
Gabe