That's fantastic, we're always really happy to hear of more girls learning technology. Great work!
We're in a transition with our Raspberry Pi right now. Our supplier has run out of B+ and we are only stocking Pi 2's through our website. We will update the description as soon as we have all of our B+ worked out of the system.
If you order through the website, you will receive a Raspberry Pi 2 with your package (as of 4/15/2016).
For Chromebooks; there are a few minor tweaks to get it to work with a Chromebook. Networking with a Chromebook is a little different because you can't use Bonjour; you need to find the IP address of the Pi once it's on a network. You also may or may not have an ethernet port on your Chromebook.
Fortunately we have a new piece of software out (available for free download) called Cinch. This works very well with Chromebooks and does not require Bonjour. You will have to download it and install it to a 4GB or greater SD Card. We can walk you through this if you want to go this way.
Just a heads up! Please let us know how you proceed and if we can answer any more questions!