i reckon if you have 22k in cash lying around then keep your rolla and go and put a deposit down on a house cos thats gonna be worth a lot more to you in the long run.
yes having an awesome car is a good thing but really its not that important... its just a car, it gets you from here to there and thats it. sure having a convertable makes u the coolest person on the block but there are a big downsides as well... such as the noise a convertible makes, and also that its twice as cold than a normal car even when the roof is up.
please dont go thinking that im an old fart (im only 21!!) that is trying to tell u not to have fun.. by all means do so... i think a new model corolla is an awesome car to have for someone your age... i'm gonna guess u have the newest car out of all your friends, or close to at least.
stick the money into a bank account that will get u a decent amount of interest... by the time you have to start working full time, you'll be halfway towards owning a house, and you'll be laughing. thats more than most 40 year olds can say, and you'll be in your early 20's. i dunno, its late, and i'm rambling, but it all makes sense to me.