Most people look at the purpose of college as being to help them achieve a successful career. If you think that way, and if your career has nothing to do with music, then, perhaps marching band will not be a good choice. Or, if you think your other subjects will suffer because of your participation in band, then, perhaps it is not for you.
However, I think college is about much more than that. I think it is a transition to adulthood, and, I think sometimes people are in too much of a hurry to grow up. So, if you look at college as the final chapter of your youth, rather than the first chapter of your adulthood, I think it is something worth doing (if it means that much to you). Many people will live for 60-80 years as adults, but only 20 as youths. Enjoy your youth! You don't want to be in a position where, when you are 45 years old, you think, wow, I wish I would have. . . .
BUT: remember, school comes first!
I think this depends on if you have enough time. You will definitely meet a lot of people with the same passion as you and make life-long friendships and get some good exercise in as well! I think that if you want to continue playing your instrument in college it is important to set tie aside to activities like these.
I spent time in High School and drum and Bugle Corps and I loved it. I was able to meet many interesting people. If you have time and enjoy it I would also say yes and these are Memories you will never forget.