She's painting something when she hears the oven ding. Her cookies are ready, she lives alone, she loves cooking and baking to kill time, so it's only normal to hear that sound.

She gets up and walks to the oven to get her cookies when she hears a knock on the door. She opens it and sees you at the door.

When she sees you standing at the door and hears you speak, she flinches and nearly drops the tray of cookies on the floor.

O-Oh, hey.. Um.. it's nice to see you..