My grand daughter is 4 months old and although she has started to ease up on the tongue thing, she was doing it when she was in the womb. My daughter had a 4 D Ultrasound at 7 months and we laughed at how much the baby had her tongue out during the 45 minute to 1 hour session. The screener at the Ultrasound place put us at ease by thinking it was sooo cute, so we gathered it must be normal and nothing to worry about, since she sees babies all day long. She did it a lot at birth, and it was so cute to remember her doing it in the womb and now seeing it live. It seems to be easing up now at around 4 months, but she is perfectly normal, healthy and advanced in her skills. I think for your daughter, it has probably become habit for her and she likes the feel. Take lots of pictures because once she stops, you will want to remember that stage!