Get some reflectors and proper lighting if you don't have them, look at lots of examples online, scout locations that are both beautiful and meaningful to her, and shoot some samples now to make sure you're not getting in over your head so you still have time to book with someone else. Last thing she wants is pics that look like Dad took them in and among everyone else's.
No offense intended, btw. I can shoot a lot of things, but portraits are another thing entirely, and if you haven't worked with lighting then it could be a nightmare.