I also saw the show in Boston and it was wonderful. Very moving, I think for women in particular it will strike a chord. You've also got fans of the movie, and Sara Bareilles (not to mention some Orange Is The New Black fans that will go for Kimiko), plus it seems to be the most anticipated show coming this season and with Hamilton being impossible to go to, I think a lot of people are going to run to this as their next-best-thing.
It won't do as well as Hamilton or get that hype but I think it will get a really positive response and run for a while - definitely until October. I saw it and found myself in tears numerous times simply because it spoke to me so much, so unexpectedly. After seeing it, it stuck with me for weeks, my mind kept wandering back to it. I think with it having that potential effect on others, it's going to be successful.
Your friend is being silly. Stress not. Have a great time. :)
If I show you the darkness I hold inside, will you bring me to light?