If you are going simply by score, if the targets had 12 rings, that would make the possible score 300 - If you shot all 8's (vitals) that would be 200, so you were close to shooting all vitals.
If the targets just had 10 rings for a possible score of 250, (which is all I really count anyway, cause 12's are meaningless) you still didn't shoot all vitals, but "score wise" you would have done better.
All in all it sounds like you had fun, and that is like said above all that counts.