1- They play loudly. During the first 10 minutes it's going to be uncomfortable but then your ears will adapt.
2- I am introverted as well, but I can tell you that Dream Theater fans are the coolest people. I went alone and seated alone but it didn't feel like so. Everyone is so chill and I met a few people during the line for the meet and great. Trust me, everyone is just like you. I felt safer there than I have ever felt in another public crowded place.
3- BRING WATER. Unless you are going to sit your butt down, you're going to need some water because it gets pretty hot.
4- Get ready to have the time of your life. This tour is amazing. You're going to enjoy it for sure.