3 months certainly won't be enough to become a pro, but it's plenty to get consistently decent pictures if she's motivated enough to learn how to use a DSLR properly. As others have suggested, it'll take a lot of reading, taking pictures, reviewing them, and trying again. Here's how my initial learning progressed:
1st month: No idea what I was doing. Pictures were consistently horrible.
2nd month: Results got better as I learned how to properly set ISO, SS, and aperture. I started getting used to my lenses and knowing what their limitations were.
3rd month: Felt confident enough to shoot at a large school event as a volunteer. Many shots came out all right, and with basic PP (cropping, WB, exposure) many more came out nicely
4th month: Basic skills got better, albeit at a slower rate. I picked up an OCF and started playing with that