I wouldn't say premature, I'd say pro-active!
OP, your girlfriend will be so happy that you thought about it so far in advance!
UltimateDisney, although unofficial, is quite accurate. If the Disney Stores do a pre-order for it and you live by one, you may want to consider pre-ordering it there because there's a good chance the pre-order will come with a set of lithographs! That would be a wonderful compliment to the DVD.