I don't think your first score is really indicative of how well you can do. You have to get comfortable with the test first. I started out at like 148 or something, didn't take a class (just studied on my own), and ended up getting a 165 on test day. I'm sure having the class will be a big boost to you. Just keep monitoring your test scores as you progress. If you're not up to snuff by test time, then you can consider your options again.