I don’t have my copy of the play on me, but it’s the character Emily who gives that speech in the third Act. She … (Do I need to give a spoiler warning for Our Town?) … gets a chance to go back to her earlier life after she has died, and she tries to reach out and talk to her mother, for example, who just treats it like any other day and keeps making breakfast. Eventually Emily realizes that she really can’t go back (I’m not making much sense, I’m sure, but while I have a clear mental picture of what happened in the play it’s been a long time since I was in it in the tenth grade, so I don’t know how to explain it).
She returns to the graveyard and the afterlife with all the other people sitting around doing nothing much but being dead, after giving the goodbye speech.
Three acts. Didn’t Emily’s mom want to go to Paris or something but never did and gave the money she saved for the trip to Emily? (Sorry, I always remember the little details like that.)