Hi Shane and welcome to the Forum!
16gb is fine but movies take up a lot of space, so if she wants to keep a few movies on it, the 16gb may not be a big enough storage option. Although she can store the movies on a PC/laptop and just download them to the iPad when she needs them.....it's all about controlling the content on the iPad at any given time.
As iJamesH has said, if you can afford it, a bigger storage iPad would be much better with less content management to do regularly.
Many members here only have the 16gb and are happy with the size, we also have many members who wished they had bought a larger storage iPad as you cannot add storage to an iPad after market. It's all a personal thing and what you want to use your iPad for, but if it's movies, I would go for a larger capacity.