I have to agree with letting her get used to the horse from the ground first. And don't be in a hurry about trying to get her on the horse. You want her confident around him, not rushed.
Help her learn how to groom him, feed him, how to halter and lead him, etc, and when she is ready, and confident on the ground around him then start helping her get ready to ride. If she is not comfortable on the ground around him, she certainly won't be when she gets on.
"The ideal horseman has the courage of a lion, the patience of a saint, and the hands of a woman..."