First, ignore the "potential alcohol" scale on the hydrometer - that is for wine or other beverages that ferment completely out, to dryness, which is not what happens with beer.
Secondly, your hydrometer reading isn't 'off'. Assuming that your hydrometer isn't broken and you're taking the reading when the wort is around room temperature, if the hydrometer says your original gravity is 1.060, that's what it is. What you don't know is how fermentable is your wort - how much of your wort sugars will be eaten up by the yeasties and how much will be left.
I would suggest just relaxing, let it ferment out and see where the final gravity ends up. I suspect your beer will be just fine! Cheers,