I would suggest it is always easier to work up from you to her. After all, suppose you tried it the other way (down from her to you) and she had twelve children? How do you know which one is your direct ancestor?
Sometimes it can work the other way. When I first came here, my gr-grand was here, with a couple of greats above him. So I built down from him because I knew exactly where to go and it was only 3 generations (and nowhere near 12 kids!). If it'd been more than that, building UP would be the better way to go for the reason Ros stated.