I'm in college for Chemistry (Professional Emphasis, ACS certified) and I'm going to be a Junior in the fall. I didn't get picked up for any REUs this year so I'm considering purchasing a GRE prep course from The Princeton Review (the same people I went through for my ACT prep a few years back) and taking the GRE for the first time this fall.

Is this too early? Or is early good? I asked my professors; they told me starting early is good but I figured I'd ask here and hopefully get an informed outside opinion before I spend the money.