castingman,
If you have an assembly model, you should have one part only that is set to "fixed". Unfix it and move everything. You have the option of moving to a co-ordinate.
If you have a part model, your life is way more complicated. Your origin is somewhere in the plane of your first sketch. If you want it in that plane, you can open the sketch and move it around so that the origin is at the corner or other feature that you want. If you did the rest of your modelling carefully, everything will not screw up.
I have not tried to move the origin from my original feature to another feature. This calls for a clear understanding of how your model works. Try selecting your desired origin feature and disconnecting all of its features from the preceding features in the history tree. You might be able to move it to the top of the tree. I have not tried this.
JHG