D.D.
If she's very active I'd suggest putting the mattress directly on the floor so that if she rolls off she won't have far to fall. I never had much luck with the guard you put on the side of the bed.
Also be aware that she'll get out of bed a lot in the beginning. It's like anything new so make the move when you don't have a lot going on in the household and you can use a lot of patience to keep guiding her back to bed.