Loud a boy your age needs to go to the hill in Boulder. Get on one of those rooftop bars near Broadway & Pleasant.. find a table that looks somewhat east towards campus. Later you'll see the show from Folsom, probably catch pieces of Longmont and Louisville too. But you'll be so busy looking at the locals you'll probably miss the fireworks altogether.
If you go mountains, Glenwood Springs actually has a nice show.. again if you can eat outside you can usually see them from your seat, did this once years ago from the Bayou cajun restaruant and it was excellent.