Also, having never been a teacher before, I really don't know where to begin. I try going over basic things with her, but she never seems interested. Does anyone have any recommendations for homeschooling materials that may be helpful?
I've worked with 4 year olds for the past 3 years and will have my teaching degree in December. You so don't need one at all in order to teach children, but I tell you my qualifications just so that you know I've got a little background.

Most 4 year olds have short attention spans,so if you're attempting to sit her down and teach a formal lesson like on letter recognition etc you'll want to limit it to no more than 15 minutes. They can't handle anything longer than that in most cases. I also don't know if you want to spend a money on a curriculum yet either. There are tons of resources on the internet for basic emergent literacy (beginning reader) and beginning math skill ideas.
You'd want to google things like: letter recognition, basic math concepts for children, and just whatever you want to look at and add "teaching ideas" to the end of it.
But HONESTLY... you don't need any of that quite yet. Books, picture books, plenty of them for her to play with and "read" and you read with her. Being conscious that EVERYTHING can be made in to teaching materials at this age is about the best resource you have. Let her put on mommy's and daddy's clothes, take her to the park, look at flowers with her. Play High Ho Cherry-os, and Candy Land with her. Count cars as they pass by, talk to her about the letters on cereal boxes, and count how many cans of soup you're buying at the grocery store.
I'm a huge fan of
www.starfall.com for a computer activity for reading, kids love it. Not saying that they should spend an extended period of time on it ever. But it's cool. Oh and
www.spellingcity.com later on.
If you talk to her having school at home, and set aside a consistent time each day for "school" (we're talking like 20ish minutes, maybe right before or after lunch). I think that would help wane the question asking. Routine is so important to the younger kiddos and will help her see she's going to "school. Heck thrown in a backpack with some "school supplies" in it and she'll be golden. But again right now "formal instruction" even in a public school environment is very limited because they aren't ready to sit still for the many many hours public schools require them to later.
PLEASE Don't put in public school if you don't have to, trust me I go every day and want to cry because I see the effect this government schooling is having on these children every single day. What benefit is there, honestly all they are doing every day is trying to make children fit into a mold, and learn about what they deem worthy. Kids have no choice in what they learn about, it doesn't matter what they're interested in and eventually they just quit being interested.