Mrs. Pete, make sure your daughter understands that:
Although it is possible to be on your account, download the books she wants onto her Kindle, and then deregister from your account, and reregister to her own new account,
the books won't be accessible to her if she does anything other than read them.
By that I mean if she reads something, decides to delete it from her device or try to send it back to Archives, it won't go to the Archives of her new account - it will be gone for good.
It's dicey as to whether it's "legal" to do this - it's clearly against Amazon's TOS but I also have had it explained and sanctioned by an Amazon employee who walked a friend through it with my Kindle when she first bought her own instead of borrowing one of mine. She probably has at least a hundred books from my account on her Kindle.
and that is why I recommend adding calibre - you then have your books on your computer - and when you take them off your kindle, you'll still have access to them on calibre.
Also on kindleboards.com one of the moderators posted that she or others post about registering, deregistering, and then re-registering... I'm not sure what to put in the search to find how they do this...