What he said is in fact true -- which is shocking because it came from the mouth of a police officer. It's civil not criminal so it won't go on your record. It shouldn't get back to anyone. Pay the fine and you won't hear of it afterwards unless you get in trouble again. If you do, Attorney Richard Foley is a fine New Hampshire attorney. 603-433-1303. Godd luck and stay out of trouble.
It is a violation level offense so it does not need to be reported as a criminal conviction.
If you were charged as being a minor in possession RSA 179:10 the fine would be $250, and the NH DMV should seek a 90 day to year loss of license, unless the Court specifically orders DMV not to suspend.
If you were charged under RSA 265-A:44 it is a fine of $150, with a potential 60 day loss of license unless Court specifically orders DMV not to suspend.
There is no need to put this on a college application.
Feel free to call for more information.