We got our daughter one for her 13th birthday, she is now 14. She does ok with it so far. She is in our family plan and has yet to exceed the alotted minutes. But if not for unlimited text she would definately put us in the poor house.
She use to carry her first phone to school, then I got her a
Rumor phone with a full keyboard. Text Heaven I suppose cause the first day she took her phone with her she sent and received over 200 messages! Needless to say she no longer carries her phone to school.

And I told her that that wouldnt change until she is driving.
But all in all she does ok, I don't regret it. Our 2 year old probably won't get his first phone until about the same age but heck the way things are going...........
I didnt have a cell phone of my own until last year (34) We didnt have cell phones when I lived at home but if we did I can assure you that I wouldn't be one of the one who had one.
