It could mean she has low tone. My ds always had his tounge out like that. At 9mo he was evaluated bc he would not eat much pure or bottles. He now has a therapist once a week and no more tounge issues.
DS loves to have his tongue out too, I thought it was more playing with is new teeth. But now that you mention a therapist, I wonder if it has to do with his eating problems - he gags on anything textured, the instant it hits his tongue.