I have become a trophy hunter at this stage in my hunting life. My freezer is easy to fill with all of the extra doe tags available so why not. My policy and my wifes' is that if we are not willing to spend the money on a taxidermy fee than the buck walks. My buck wasn't a monster by any means this year but he was a dandy and what made him a trophy to me was how I called him in and filmed it all on my own. So to answer your question was it bad to take a little buck just 'cause it was the last day of season just to put points on the board for some stupid deer contest when he could have walked and grown for next year...well we each have our reasons and nobody can judge someone else. If this deer challenged you and left you withsatisfaction of your hunting skills;only you know.
P.S. Congrats on your buck!!!!! All deer taken with a bow are a trophy!!!!!!