Unless she specifically asked for studio shots, don't think that you have to automatically shoot like that.
If she is really looking to get into modeling and doesn't need those static headshots, then make it fun and go explore outdoor locations! You can get a HUGE variety of shots by just walking 1 block somewhere downtown, where ever you are. If this is the route that you want to take, go out and LOCATION SCOUT. It's so important, that's why I put it in caps. Hahaha. But seriously, figure out what time of day you are going to go shoot and then go explore where you are going to shoot at that time, you will be able to get a feel for not only cool locations, but lighting. And then you look much more composed on the day of because you know exactly where to go.
When it comes to time of day, my personal favorite is noon. People will tell you to only shoot late afternoon/right before sunset but that light is generally not as nice as everyone makes it out to be. If you shoot at noon, and especially if you are shooting in an 'urban' environment, you have the best lighting ever! It's called open shade and it will be your best friend for life. When it is noon and the sun is at it's highest, you are going to get these awesome areas of shade, where it's basically a big soft box and it lights everyone perfectly. And even more awesome then that, is that you now get a piece of pavement/sand/etc where the sun is reflecting off really hard into your subjects eyes, and now you have perfect catchlights without having to use anything but the sun! And catchlights are very important, if your subject does not have them they will look dead. Seriously.
If you don't shoot at that time, or get the right combo of shade/reflection with just the sun, I recommend bringing a reflector. It's going to be necessary, especially for the catchlights. Personally, I'm not a huge fan of using anything BUT a reflector so I can't really weigh in on using strobes/flashes/etc.
Anyways, what I'm trying to really say is be prepared. Be as prepared as you can be before the shoot and you will be much more relaxed, which will allow you make everything run much more smoothly, and you will look more professional. Scout your locations (if you are going outside the studio), decide on your lighting beforehand (but bring backups just incase it doesn't end up working out), and most of all, research posing and know how to pose your subject. They are going to be looking at YOU for what THEY should be doing, and it's your job to direct them.
Lastly, here's some links to some helpful articles related to what you are doing.
http://www.michellemooreblog.com/2010/02/25/seattle-professional-headshots-jane-my-best-friend/
http://www.seniorologie.com/location-scouting/
(Even though it's for seniors, it applies to modeling as well, especially with the girl being younger)