Your friend certainly didn't know much about what kind of snake he/she had. That is MOST DEFINITELY a very typical looking cornsnake! 
And yes, it is certainly on the thin side too. It is sort of dificult to say exactly how old it is, because he didn't feed it very much or often, but it is very likely two or three years old.
You should get yourself a good inexpensive book on cornsnakes, and there are several good authors of these that I know personally. One being Don Soderberg's excellent book "Cornsnakes in Captivity", and Kathy Love's "Cornsnake Manual". These can be found at many pet stores, online, and most any reptile show. You really do need to understand their very basic care. Once you do, you won't have to ask questions one at a time on the forums like so many do when problems occur. The most important thing to remember is to PREVENT them from happening in the first place. These books by these two very experienced authors will make sure this happens if you read it. They are only a few bucks too, so there is no excuse whatsoever to not get one.
The snake should be fed a rodent that is big enough to make a pretty noticable lump in it's mid-section of the snake, so feed it a young hopper mouse that is "slightly" bigger than the snake is at mid-body. Keep in mind, the snake can eat a meal far larger than it's head because their upper and lower jaw un-hinge by way of elastic-like ligaments, and the lower jaw even separates sideways as well, so do not be fooled by this, just feed it a meal
as I mentioned that is slightly larger than it is at mid-body, and this will be fine. You should do this about every 5-6 days.
Anyway, tell your friend he/she totally SUCKS at snake identification..LOL!
~Doug
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"a snake in the grass is a GOOD thing"
my website -serpentinespecialties.webs.com
