In my house, I have both a digital piano (Casio Celvianno) and a Baldwin upright. I'd say that I spend a little more time practicing on the digital than the acoustic. The reason I have the digital is so that I can practice late at night in my own room, without waking the entire family. Up until a reasonable hour, I use the Baldwin for practicing. I notice differences between the two pianos in touch, but I easily adjust between the two, as one does when playing on any piano that is unfamiliar. The biggest difference between the digital and acoustic pianos comes in the sound quality and overall feeling when playing. Because the digital piano doesn't sound as "real," I essentially use it for practicing technique. I try not to delve into musicality and performance when playing in my room, and focus more on fingering, memorization, sight-reading, etc. When I'm upstairs on the acoustic piano, I take more advantage of being able to hone the musicality of whatever piece I'm playing.
My point is that on a decent digital piano, ie one with a comfortable, realistic hammer action, 88 keys, and a decent sound, you can practice everything sufficiently, with the exception of musicality and performance. Because a digital piano is physically different to an acoustic, no matter how well-made the digital piano is, it's no substitute for playing on an acoustic. With this note, I think it is very possible to practice and "get good" on a digital piano, but only with the supplemental, regular-use of an acoustic. Hopefully, you're using a grand piano some of the time as well. I play digital and upright pianos at my home, and then once a week, I play a grand for an hour at my piano teacher's house. It isn't by any means necessary to own an acoustic piano, but make sure that you are playing on someone else's at least a few times a week if possible. Maybe your school has on that you can use (I often play using one of my school's pianos).