I got home from work today wanting to check out the anniversary event (obviously i’m leaving it till the last minute) and the red pentagram is no longer at the old ruins. Did i miss the event?
Yes, if the red pentagram is gone it is over for this year.
https://us.diablo3.com/en/blog/22855173/the-darkening-of-tristram-returns-january-3-12-31-2019
Exclusive rewards and challenging enemies await you, but they won’t last forever! The cultists have begun appearing since December 31 at 4 p.m. PST, and the portal opens January 3 at the same hour. Both parts of the event end January 31 at 4 p.m. PST.