This is such good news!! I'm excited for you that you are helping your DGDs learn to sew.
What will be the first projects? Dolly Quilts? :)
I just got the 6600, and it's my third Janome, so yes, I'm sold on them. I just had a quick look comparing your machine to the Janome Gem Platinum. That's what seems to be the favourite for those purchasing a machine to take to classes and leave their high end (and HEAVY) one at home. NOt a lot of difference in the two, so I think you have a good one!
For the price difference and the number of DGDs that will use it, you'll never regret that little extra $$
(..... besides now you have one to take to classes yourself! :) BONUS!!!)