Good luck dude, ignore the haters on the forum. At no point did you come across as cocky or rude, and keep it that way. Some forum members aren't too fond of college kids in 3ers... (mind you, it's only a 3 series).
Do hang around and educate yourself on the cars before making that huge financial decision.
It'll definitely go a long way in your decision and you'll get a better feel for common strengths, issues and the market value of the car that you're gonna eventually get
These cars, especially older ones out of warranty are not cheap to fix when something goes wrong. Parts are one thing, but labor adds on (a lot) more than you'd initially think.