Cooper - there are entire books on the subject. I will try to hit some of the basics. Probably the easiest way to get started is to go to an archery range or a pro shop. Typically indoor ranges have a pro shop (that's where they make their money). Many pro shops have a shop range.
You need to know some of the basic verbiage. Your GF is interested in traditional archery. A bow with gears, cams, pulleys, etc. is called a compound bow. She is going to need a bow, arrows, an armguard and either a finger tab or a glove. She should consider some type of quiver as well. String silencers and string wax are nice to have but not essential.
Traditional bows are either recurve or longbows. However, there are hybrid longbows called "reflex/deflex longbows." Let's not worry about that for now.
To start, a recurve is generally considered more forgiving and easier to learn with than a longbow. However, this is not true for everyone. By renting equipment at a range or trying out a lot of equipment at a pro shop, you can see what bow is best for you. Your GF should be tested for eye dominance for a general indication of whether she will be shooting leftie or rightie.
Most beginner traditional bows are made overseas

However, once your GF gets good enough for an intermediate or advanced bow, there are a lot of great custom bow makers here in the states
Bows are measured by length and draw weight. Length is not so important. With a modern bow, anything over 60 inches should work just fine. Draw weight is critical. The most common mistake for a beginner is to get too heavy of a draw weight. There is a lot of confusion here because compound bows have a mechanical advantage, once you muscle the string past the break point, you are able to hold it at a very light draw weight. As a result, people tend to get steered towards very heavy bows. For women especially, I recommend a bow no heavier than 25 lbs. to start.
For specific recommendations, I would start with a take down recurve, 62 inches and a 20 or 25 lb draw weight. Take downs have interchangeable limbs so you can get a heavier bow by swapping out the limbs and keeping the grip that you are used to.
There are 3 theories on aiming a traditional bow. If she is going to shoot Olympic style, she can just get a sight. If she is going to shoot traditional style, then it is instinctive or gap. I will not try to explain the difference here. When I teach instinctive I explain that it is like throwing a ball, both eyes are open and on the target. Don't try to line up the point of the arrow with the target, rather rely on your instincts and muscle memory. Start close to the target, but not so close that the arrow cannot recover from paradox. Ten yards is ideal for a new archer.
It is critical to have a consistent anchor point. Pull back the string so that some part of the drawing hand touches some part of the face. Don't pluck the string on release, just open the fingers. Easier said than done!!!
Shoot a lot of arrows. Practice is everything.
Carbon arrows are very durable and accurate, but expensive. Aluminum is accurate and less expensive but they are difficult to find. Wood is cool but does not last long and not very accurate at all. Arrows must be matched to the bow by an experienced archer. There is a lot to tuning arrows. I have spent hours in the shop, getting my arrow specs. down.
To give a personal example, I started archery in my early 50's which is very late in life. I was out of shape and could barely pull a 20 lb. bow when I started. I kept at it and shot a lot of arrows. I started to improve and built up to a 40 lb. bow, which is where I will remain. (I do not hunt.) I shot a longbow for a while and then bought a custom recurve. I make my own wooden arrows using specs. from a pro shop. My wife and I teach archery at our local rec. center and I am a volunteer instructor at our local archery club. We have started adding slingshots (Trumark "wrist rockets") and paintballs for our archery kids. They are a great way to introduce archery basics and to build up some muscles for form.
It is a great sport. Stick with it. Ask a lot of questions. Have fun.
Here are some links:
www.stickbow.com - great forum
www.3riversarchery.com - everything traditional
www.slingshotsusa.com - if you want to try a slingshot
Let me know if I can help you with other questions.