Way to go on registering for the tri, zu!
You're amazing!!
Yeah, it does suck when you're not allowed music in races. I always make sure I know ahead of time before signing up, because music is my motivator when I run. I always run with just one earbud in, so I can be aware of the people around me. However, when you're doing multiple events instead of just running, I can definitely understand the no music rule.
Cheerleaders totally make a difference. On my first year doing the big 10k in Vancouver, some of my friends surprised me at several spots along the route, and were there cheering. I totally cried, but what's cool is that they were there EXACTLY when I needed a boost of encouragement. The finish line for that race is always awesome. There are literally HUNDREDS of people cheering everyone on at the end, and that really helps me get across the finish line. Even though they don't know you, they're so happy for you to finish the race, and that's awesome.