Since this is your first car I'll just assume you are going to be buying used. If you are considering buying new that would be my first but of advice; don't! Lots of unexpected factors come into play for young people buying their first car that aren't expected. For example, when I bought my first car I was making about $250/week and made the mistake of buying a Lexus that landed me with a $400/month payement. I was thinking "I make a grand a month and still live at home, so I can handle $400 no problem!" But then the insurance came in at around $200, then gas, and so on. Before I knew it almost all of my pay was going toward my car in one way or another and I had very little spending money left for clothes, going out, etc.
Keep all of these things in mind when buying your first car! The last thing you want is for it to change your lifestyle in a negative way rather than positive.