are they actually as good as everyone says? its my first car...

They are nice...must be nice for your first car to be a Benz!!! High Roller!!! :)

How big a chunk did it take out of your trust fund?

I think that as a first car it is a very extravagant choice, but to each their own.

A Mercedes-Benz is well, a Mercedes-Benz. They build some of the best cars in the world, and the SLK is a very good example. They had the first retractable hardtop convertible in 1997 with the SLK230 Kompressor. (I believe they did; Peugeot may have had it first, but I believe Mercedes was the innovator)

Enjoy your car, just make sure not to crash it, always wear your seat belt, and to maintain it on a regular basis.