Children and smart phones *UPDATE*

How old do you think a child should be before they have a smart phone? My daughter is 6 and really wants one, she wants it for you tube and she likes to make videos on my phone of her baking and what not. I would not let her have a SIM card in it and would check it multiple times a day?

Thank you for all your opinions! Me and hubby have decided on an iPad for her, she will be using my Apple ID so she can face time her dad and grandparents! I will be checking it everyday and she will only have a set amount of access to it unless for homework purposes as her school have online homework that she currently does on my iPad