Hi there,
I used to work in retail selling Digital Cameras so let me be the first to point out that there are other brands you should consider.
I myself am a Canon shooter so i may be a little biased in my response but i don't mean to be. Canon, Nikon and Sony are the 3 brands i am talking about.
If you are dead set on Nikon right now then i would suggest you pick the D5300 as although its cheaper it has much the same features as its more expensive big brother, the D7100. Especially for learning, this would be my camera to offer you anyway (If i was selling you a camera in store). However, You should think carefully before rushing into Nikon as once you have committed to a brad and purchased the lenses you are stuck there unless you want to splash some cash and buy a whole new kit again.
Canon's equivalent is the 700D and it is also a fantastic camera, even more so than the D5300 if you are wanting to do some video as well. Remember, for video the higher the megapixel count the more issues you are going to run into in terms of Anti Aliasing, moire and low light performance. That said, don't let me turn you off the D5300, for all intensive purposes the Nikon is better than the canon in almost all instances when it comes to stills.
Sony's equivalent is the Sony A58 and i think that this camera is a good middle ground between the 700D and the D5300. Besides that Sony, are becoming know as the low light performers, especially their mirrorless cameras (A7 series) Which is a bit more pricey.
Just to re-iterate, when you first buy an SLR you are buying into a BRAND not a MODEL. So think of it this way. 'Most' DSLR owners DONT upgrade their lenses but instead opt to upgrade their cameras. So if you by the Nikon now you are investing in Nikon lenses and will therefor have to stay with Nikon for future upgrades. So the camera body doesn't matter as much as the lenses. Do a bit of research on the quality of each brands lenses and make your decision from there.
I hope what i layed out for you is easy to interprate.
Thats my 2 cents.
Hope it helped!