How should I draw this child..?

I'vepromised a young girl out of a few from a Art school Im helping at that I'ed finish a portrait of her. She's quite adoreing, and shes become a good little friend of mine. She was wearing a ponytail, and thats how I remember her. Shall I draw that? Or long hair? Possibley pigtails. She's a blonde little girl with a heart shaped face and high cheek bones. Freckles, and green eyes like a forest. I want to make it good for her, I've got this kid counting on me, and I dont intend to let her down! Im setting a example for the other children aswell.. Im very good with kids, infact, I love them around. Anyone have an idea on what view I should do this? ^_^ Im open to anything.