Welcome to stangnet, now you have asked one of the most, ahhh, lets see, how do I put this.
Let me put it this way:
How fast can you afford to go?
Now don't get the wrong impression, that is a very true stantment. Also do you:
Have a place to work on it
Have the knowledge or the will to learn
Here is my advice.
Buy a nice daily driver to get you back and forth to school/work, take auto shop classes (do they still offer that?) plan a build for this car based on what you want to do with it.
That's what I would do at your age knowing what I know now.