Did you have someone else measure your torso length? I tried to do it myself three times and came out with three different measurements ranging from 16" to 17.5". Finally I got a friend to do it. Both she (with measuring tape) and the local REI store (with their pack measurement gizmo) came up with 15". REI has an excellent video on their website how to do the measuring and another one on how to adjust a pack.

And did you have your torso measured by someone else before you ordered the pack?

Your height has little relationship to your torso length. Some people have longer torsos and shorter legs, while with others it's the opposite. That's why the torso measurement is so critical, and is not something you should do yourself.