My first answer is nope because it's out of warranty and has a first car you aren't used to car repair surprises especially being a benz. The c300 is also crap, if you can't get the c350 don't even bother.
I suggest you look into those years c-class and see frequent occuring problems. Then see how much it cost to repair. After that add in regular service cost and if that fits your bill.
For 13-15, I'd suggest you get a sporty like japanese car for a first car.
I owned a 09 C63 (same model but different in various ways), it had problems all the time leaving me stranded a lot. Not sure about the C300 but please take some time and research common problems.