not trying to be rude here, but how can we possibly give sounded advice/recommendation without knowing some of the most basic info. OP made it clear he doesnt have the basic knowledge about these things. so i think we need to guide OP towards the answer he needs
OP, could you give us more information so we can help you better?
> what camera is your gf using now? (e.g. phone? small point and shoot? DSLR looking camera that cant change lens? small camera that can change lens?)
> what sort of budget do you have in mind? (these stuff normally starts around £300+)
> are you guys sporty and travel a lot? is your gf likely to use it a lot to take sport photos?
> we need to understand your gf true desire/requirement for a DSLR (the reason for upgrading). the reason i ask is that, DSLR is generally regarded as better image quality than small point and shoot machines but they are also bigger. but there are some middle ground solutions. they are called Compact System Camera (or mirrorless camera). essentially they have the same size sensor as entry level DSLR and will produce similar result. these machines are usually smaller than DSLR counterpart as they do not have an Optical Viewfinder (the little window that you look through to take pictures). Instead they either have a Electronic Viewfinder (similar to optical, but this is a tiny LCD screen that you can look into), or sometime they will not have any viewfinder and only have a LCD screen like a point a shoot camera. to give you some example of these machines: Sony NEX-3n, Fuji X-M1, Canon EOS-M. There are some even smaller machines like Panasonic GF5, Olympus E-PM 2. These mirrorless cameras are smaller than DSLR, but to make them smaller, most of them will not have as many physical buttons on the body like a DSLR. The functions are still there, normally hidden in the menu somewhere, so accessing these functions is normally not as quick as a DSLR. so going back a little bit, you need to find out if your gf really need the speed of a DSLR and also the Optical Viewfinder. (some people prefer looking through the optical viewfinder, as you can physically see the object and not through LCDs, but some dont feel there is a need. )
> another aspect we need to determine is the lens coverage. in very simplistic terms, there are 3 types. wide angle, normal, telephoto. wide angle is normally used for landscape photos where you can cover as much as possible in a single photo. normally is defined as human vision, like exactly how we see it. and finally telephoto which is covering things very far away. these are described in "XXmm", search focal length if you want to learn abit more about it. typically a DSLR or mirrorless system will come with a standard zoom lens that will cover abit of everything (typically you will see numbers like 18-55mm). on an entry level DSLR, 35mm is normal, 18 is wide and 55 is tele. most of the point and shoot camera out there will cover the same range if not more. so going back to the original question, does your gf want super wide angle or super tele which normal photo and shoot/phone will not be able to provide. The reason i ask is that, if these are the requirements, you may need to spare more budget on the lens. quite a few manufacturers offer dual lens kit which covers a typical range of 18-55 and 55-200.
one of the most common misconception when people get into DSLR is to assume it will do better zoom than a point and shoot. this is not true for the similar price machine. because the smaller the sensor in the machine, the smaller than lens can be. for DSLR/mirrorless camera, the sensor is massive, so the lens is also massive in order to cover the same range as a point and shoot. you need to find out if your gf thinks the DSLR can do super duper zoom.
