Careful with that one!
She may wear plaid shirts!?!? attachFull24793
And comfortable shoes!!!! 
The way I see it is pretty simple, she is an adult, she has money to spend and desires to spend it on a Rocket. Let her spend it. One of a few things may happen;
1. She will be scared after a ride or two and trade it in. Not Likely from the sounds of her.
2. She will drop in in a parking lot or somewhere and get the help she needs to pick it up and keep on going. Or you can teach her the proper way to pick up a down bike and she should be good to go.
3. She will hit the gas when turning a corner from a stop and will swap ends and go down, kind of controlled, and will learn much respect for the beast.
4. She will ride the tires off of it, getting more proficient with every ride, eventually tiring of the stock Rocket and send it off to Carpenter for an upgrade because like so many of us, she loves POWER.
But, the bottom line for me is would it be my place to try and talk someone out of buying a bike I know they want? I don't believe so, as an adult she knows what she wants, probably is keenly aware of the risks involved, and has the money and the desire to step up to a Rocket. You should encourage her, along with a lot of "please be careful", etc.
bob