What's the hurry? Only a few states even let juniors take the exam. Most require you to be a senior in college. You want to only have to take it once, and if you haven't had all of your required undergrad courses, you'll likely struggle on those questions. You'll probably be in a much better position next October, or even April 2011.
I agree, I want to pass on my first try. Do you know if the number of pass/fail attempts are accessible by employers?
No one can see the number of tries. Either you've passed it or you haven't, and that's all employers really care about. Other than when I applied to take the PE, I've never had to prove that I actually did pass it.
Go to your school library and see if they have the NCEES sample exam (mine did), otherwise I would highly suggest buying it and seeing how comfortable you feel with the material. It is a fairly accurate representation in terms of content and difficulty. I wasn't trying to discourage you from taking it from my earlier post, but you seemed like you weren't very comfortable with the material and more courses in your major will only make you better prepared. I certainly would try to take it while in school, but I'm not sure there is an advantage with taking it so early, especially if you aren't sure that you know the material.
Have you taken engineering economics yet? They are fairly easy questions to get right if you know how to use the tables.