Thanks for answering the questions. I think it's great that you're asking for help and advice. I know this response is long, so feel free to ask questions!
I think it's most important for you to get a better idea of what good rabbit care looks like, since it sounds like the person who gave you the rabbit did not tell you much, and what he/she did tell you isn't very good. There are a lot of people who sell rabbits and they don't actually know how to take good care of them.
If you go here:
https://www.binkybunny.com/BUNNYINFO/tabid/53/Default.aspx , there are easy categories you can click on to read up on the different components of rabbit care (ex. Cost, healthy diet, litter training, habitat...). It's a very easy read, and if you have any questions or are confused about anything, definitely feel free to ask on here!
As
@Hermelin says, right now, it's most important for her to eat
hay. No matter what age a rabbit is, hay is the most important food for a rabbit. If you do not have hay, you'll need to buy it at a pet store (easiest place to find it). At a pet store, there will be a lot of stuff for rabbits that aren't very good. "Oxbow" is a good, trustworthy brand for rabbit food and supplies, so if you can afford Oxbow Timothy hay, that would be great. "Kaytee" is another brand that's slightly worse quality, but they also sell Timothy hay that's good. If for some reason Timothy hay can't be found, Orchard Hay works as well.
Carrots and banana are rabbit-safe treats, but they will spoil your rabbit's appetite. Just like how we won't eat salads if we're offered candy, rabbits won't eat what's healthiest for them if they're eating sugary food. I would stop giving carrots and bananas all together so she can get used to eating hay, because again, it's really important she eats hay. It helps keep her teeth short and it will keep her stomach healthy (hay "cleans" a rabbit's stomach, and keeps them healthy).
