However, she doesn't mean March 2012. As devoted fans know, Alison (Sasha Pieterse) disappeared on the night of August 31, 2009. The show started a year later, in late summer 2010, when her body was found.
It has been less than a single school year since the show started, which means that when Marlene says it's March on the show, it must be March 2011.
That means about only seven months have passed on the show, which matches up pretty well with Marlene saying that Season 1 took place over the course of only eight weeks. Think of everything the girls have been through in under a year! It's pretty amazing that they're still fighting back against “A.”
Find out who “A” is on the Pretty Little Liars Season 2 finale on Monday at 8 pm ET/PT on ABC Family.