Zeraph

So I've had a knife (6 inch blade) since I was 7 or 8. Its a fairly good knife. In fact its hanging on my bedpost. Its a buffalo skinner. But after doing what I was told not to, I ran my thumb over it parallel to see how sharp it really was. Turned out I didn't even get something like a paper cut! I had to push down quite hard to cut myself even the smallest amount (indentation really).

Is there a standard measurement for knife thinness (or sharpness?)

Is there any other way to tell if a knife is especially sharp besides running your thumb perpendicular (or parallel if stupid/brave heheh) to the blade?

For instance, should I be able to expect shave with my knife?

Assuming proper upkeep, and sharpening stones, etc.