The choice is yours, but I wouldn't. I know and remember how lame it is to be taking the bus around and how not having a car feels embarrassing senior year but I'm here to tell you that it's not so bad. In May you're graduating it is almost over and I also went to a college were a car was not needed.
Fact is that if you buy a car now, you're going to be stuck paying parking fees to take it to college, also insurance, also repairs specially on a used car which is going to have A LOT of miles. In the end those 7k are going in the toilet cause the resell of this potential car is basically Nothing. I had the same issue when I was your age and it was hard but I stuck it out, here's what I did.
I used my saved up money (part of the 7k) and got a limo for Prom, went to a nice restaurant and got a sweet hotel afterwards, didn't cost nearly as much as actually buying a beat down car and let me tell you my Date was very impressed. WAY more impressed than she would have been if I had gone and bought a used craptastic ride and the night didn't cost me past 700$ so I kept almost all my savings. The night was amazing and yes we did get lucky.
Then I went to college, I rarely ever needed to get rides being in the city and was part of the norm with nobody having cars. The new girls I dated didn't care cause we all lived so close to each other. I continued studying and working on the side and saving money. I graduated college and before coming back home I spent all my saved up money of 4-5 years and bought a brand new 2012 Infiniti G37 IPL Performance Coupe. Luxury, Fast and absolutely beautiful all because I saved all those years and then bought the car when I actually knew I would use it. I am now 27 and all of my friends still can't afford a car like the one I bought and it certainly scores brownie points with the girls.
You get what you reap, save now, enjoy the benefits later. It was hard at the moment but now I'm glad I waited.
Cars are not cheap. There's the upfront purchase cost obviously, there are maintenance costs, insurance costs (which can be very high for a young person), gas, etc.
You'll need a lot of money ongoing for gas, maintenance and insutance.
don;t forget about insurance - that may cost you $100-200 a month