The reason why the gears "grind" because they're not properly engaged. You've probably more than likely hit 6th gear if the car is in movement instead of reverse. Either way, you don't want to not engage gears properly as it will incur premature wear and tear to your gearbox instead of your clutch.
no biggy... i've had a couple of mishaps in acquiring a feel for the timing of the shift with the tsx... if you're really concerned then maybe you should have your gearbox fluid swapped at the next oil change(to help get rid of any metal particles). i'm about to go in for my first oil change at 4K and i'm going to have mine changed. the cost is minimal and if it gives me peace of mind then why not?