Visiting a Friend in the US

[Molarmite]

I have a 16 year old friend in the UK who would like to come visit for an extended period of time. What are the odds that she could get a visitor's visa to come stay with me and my family for 6 months and then possibly get it extended for a year? This sounds like a perfect use of the visa but I'm not really sure.

[immihelp]

Very unlikely.