Okay, I suspected that - time to make an appointment to get her spayed. The hormones are kicking in around this age, and females can get territorial. Getting her spayed will be better for her health (bunnies tend toward ovarian cancer otherwise), and she won't feel as much need to defend and mark her territory.

We used to play a game with our bunny we called toreador - I'd wave my bathrobe, and she charge at and through it, grunting and spinning. Maybe try that - but make that appointment first!