is this normal for only 53,000 miles to have worn engine mounts?

Get a second opinion

I would get a second opinion as recommended. Unfortunately , from what I've seen , the mount on the fender is the most common that I've seen on that model , and as you've said , I also think the milage is to low. How long they last can sometimes be dependant on how it's driven , but in this case I'd be more inclined to say design flaw(or quality control-your choice).