It's hard to set a price to a car site unseen. Nevertheless, the car you are looking at is probably a leaser which exceeded the mileage by 2:1 so the price should be lowered for this reason by around 5 to 10%.
The bulk of these cars fall into the good condition category. This means the car must not require any major work. Its paint, body and interior must have none or very small blemishes and very minor or no rust. It should require, if any, only some minor mechanical work. Tires should be identical and have plenty of tread left. Maintenance should be visibly good.
As for the warranty, who issues it and what are the conditions? You do not wish to be covered by an irresponsible party, and you do not wish to be tied to having to do maintenance at a dealership. Look at your long term cost.
Papers should be in order and Carfax should look good.
Have the car thoroughly check by a mechanic of your confidence (pay him if required) and have him go over every inch of the car and report to you in private to discuss the purchase as a yeah or a nay and sleep over this overnight before you decide. Of course take him when you test drive it.
It's your first car, so be careful and enjoy it when everything falls in place.