But is it absolutely impossible to get into a good law school if my GPA was in the high 2's at the time of graduation?
It depends on you mean by a "good" law school. You can get into plenty of ABA approved law schools with a below 3.0 GPA if you have a very good LSAT score to compensate. Since your GPA is relatively low, the law schools are going to need to see some evidence that you're capable of handling the rigors of law school. Thus, everything hinges on your LSAT score.
Nationally recognized, elite schools are almost certainly out of the picture since they require high GPAs and high LSATs. Less prestigious local and regional schools are a possibility, however. Please keep in mind that many of these schools can be good choices depending on your career goals.
Lastly, you need to do a critical assessment of your academic capabilities and ask yourself why you have a low GPA. Law school is far, far tougher than undergrad, and if you had specific problems that held you back in college you need to make sure that those issues won't get in the way during law school. The amount of information you'll need to digest, and the speed at which it comes at you, means that you need to be able focus much more than you in undergrad.
Are there any schools that don't look at GPA at all?
And also when would be a good time for me to start prepping for the LSAT
Yesterday. Seriously, get started ASAP.