Go to college and dont worry about not knowing exactly what to study, the very fact you are there is something and you are only 21, you have plenty of time to decide on your vocation,just learn as much as you can, I'm sure you will not regret it.
Honestly, I know what I'm talking about, I made a similar mistake to you in not persueing my education, I am now 25 and still wondering what I am going to do but whatever I decide it will involve going back to college or finding a career, no knocking on doors for sure.