Ever read the bible? Maybe it's a sign that someone wishes to harm her because the snake in the bible tricked Adam and Eve into eating fruit from the tree god said not to eat from and in the time the snake had legs god punished the snake for getting them to sin and forced all snakes to crawl on their belly:) (Well hope I helped)
What does this dream mean? I was in the country with my kid and she went out to play, and when she was on her way back a snake with legs tried to eat her but I shooed it away. Then it did it again and another snake also showed and my girl was eaten.
It could be seen as euphemism for you not wanting your child to grow up too fast where you have to accept all the things that go with it- like boyfriends and relationships and being tempted by peer pressure.That's symbolised by the snake who represents temptation and desire.