When I went to college, my goal was to get a 4.0 GPA. Then I was told that people with 4.0 GPAs usually don't have lives and that grades don't matter that much. So through college, I was a bit of a slacker.
The problem is that I interpreted "that much" to mean "not much." Grades can be very important. Unless you're a very charismatic person who can network like crazy, grades will probably be a huge help in helping you stand out to get a job. It's also good to have if you're planning on transferring to a regular four year school to get a B.S. or B.A. It's even more important if you plan on going to graduate school for an advanced degree.
I know I like to joke around and kid on here, but in all seriousness, one of my regrets about college is that I didn't study hard enough and that made my life a lot more difficult than it had to be. You won't be a failure if you get a 3.9 instead of a 4.0 and don't go crazy with being perfect, but study as hard as you can to get the highest grade that you can and your life will easier for you in the future so then you can do more fun stuff like partying and so forth.