Wow, I am not alone!
For almost two years - from the age of 1 to about 3, my now-4yr old ate at least one and sometimes two meals of peanut butter every day! (We are also a Skippy family = ) I would spread it on reduced fat triscuits or the wheat/ low sodium saltines, after a while I added raisins pressed
in on top.
This is still one of her favorite meals. I have gotten her to reluctantly eat it on whole grain bread, but she still likes it plain (no jelly). We allow her to have a spoonful of it once in a while as a treat.
I worried at first over it too, but I figured, PB has a lot of protein and fiber, as well as 'good' fats. At her age, she's needing fat for her brain (and other parts) to develop properly, so it's all good! I was happy that she wasn't addicted to chicken nuggets or something else fried.
I'd recommend that you move her away from eating it on a spoon - put it on crackers, toast, bread, apples, carrots, celery, etc. It will get her to eat other things, and it will be easier on you in the long run - if you're packing lunches for an outing, it's far easier to tote along a peanut butter sandwich than a bowl of peanut butter.
Don't stress and good luck!