That's so cute! Have you taken a video of it? It's a nice memory to capture.
According to Parents.com, the developmental milestone for mimicking actions is from 8 to 12 months old, so I would believe that your baby is a fast learner.
Your baby will also imitate other actions, including undesirable actions so do be careful of her surroundings.
http://www.parents.com/baby/development/growth/8-12-month-milestones/#page=15