Yeah Renee, that is actually very low for needing tires replaced. Was the car brand new with new tires or was it used? Another thing is the manufacturer of the tires. If you have some super cheap brand tires, they may get a bit worn at 15K miles.
Most dealerships, I'm saying most as to not offend anyone, try to get as much as they can out of you. If I were you, If you havent paid to replace them, take them to a little ma and pa auto shop and see what they say. Tell them you situation.
It's always best to find a nice reputable auto repair shop. Guess nowadays its like trying to find a needle in a haystack though.
Honda wants your money, period.
Eddie