I went on a road trip with my brother at almost three months sober to an out-of-state concert. I told him up front that I stopped drinking. He didn't drink much to begin with, and he has his own health concerns and stopped drinking because of them, so he didn't think twice when I told him. He didn't even ask why! (It's amazing how I always thought everyone cared if I drank or not.)
I can honestly say it was one of the best concert experiences I've ever had. I've seen better shows, to be honest, but the entire trip, talking with my brother, remembering everything, and not feeling like garbage the next morning, words really can't describe how much better it all was compared to some of the shows I've seen in the past where I was out of control from my booze consumption.
You won't regret seeing a concert sober.