Daily Ticket Sales 30 days out

Hello all,

I am trying to create a line graph in Analytics that shows the sales for a concert each day, for 30 days before the concert. I am hoping it's easy enough to change that to 14 before, 20 before, etc. I added to the X-Axis "Order Days Prior to Performance" (see image) and the numbers aren't right. I'm not sure what's actually being pulled.

I appreciate any guidance you can offer. Thank you!