I think a nice-sized crate would be a good idea. Jack Russells tend to be high-energy dogs, though your girl might not be at first because of where she's come from. Still, crate-training her will give her a nice secure little "den" where she can safely be, with toys and things to occupy her time of course, while you're away from the house. Two dogs I know who have been crate-trained even return to the spot where their crate used to be to nap long after the walls were removed.

Once she's all settled in, you'll have a playmate for sure! She'll let you know what games she prefers, and remember, walks are a good thing for both of you. A tired terrier is (usually) a well-behaved terrier!

Are you planning on attending an obedience class with her? It might be a good idea, especially as she will be your first dog. The class will not only teach you about being a doggie owner and her about doggie dos and don'ts, it will create and strengthen the bond between you.