Try not to fret too much about the professor. I'm making a career change to nursing and already have a four year degree and some grad work under my belt (all in music, if my screen name didn't give that away). In all of my years in the classroom, some of my most dis-likeable professors (as far as personality goes) have been the ones I learned the most from. The one I'm thinking of specifically was full of himself and a pain in the butt. If I met him outside the classroom, I can tell you that I would have thought he was a jerk. But he was insanely intelligent and had high expectations and expected his students to tow the line. Even though he was tough, he was fair and I learned a boatload from him and I'd say as far as teaching goes, he was one of my better professors. A lot of times though, students can't get past a professor's personality and will give a bad review based on that. And other times, professors with extremely strict expectations get bad reviews because they're difficult to please. But if you put in the time and the work, you should do fine.
I never bother with rate my professor because I find that the reviews aren't reliable. Have you taken statistics yet? When you do, you'll learn that volunteer surveys are the least reliable way to collect data because only the people that care a lot or are very very disgruntled care enough to volunteer their opinions. So you get a very poor idea of what the population really thinks. Go in with a positive attitude. Be willing to ask questions. Sit in the front of the class. Take copious notes. Get extra help from a tutor if necessary. Take advantage of your professor's office hours. Also, a great tip is to go up to the professor after the first class and introduce yourself. Say, "Hi, I'm 'so-and-so' and I just wanted to introduce myself and say I'm looking forward to a good semester." Do that especially in a big lecture-hall sort of class where there are 100s of students in the room. Professors (and teachers in general) appreciate it when students do that because they have a million names to remember and it can help them out. They do actually like to get to know their students. And if they can remember your name and know that you are an active participant who is interested (or at least pretending to be interested lol) in the material, and you happen to be that student with an 89.6 at the end of the semester - well, then you've got a better chance of getting rounded up to an A instead of truncated down to a B (most schools leave those borderline grade decisions to the discretion of the professor and an 89.6 doesn't necessarily have to be rounded up at every school).
I still remember when I took astronomy in my undergrad. A year later, I ran into that professor at a planetarium program my university was putting on. After the program, we got to go to the roof of the science building and look through the telescope at Saturn and Jupiter with its moons. My professor was manning the observatory and when it was my turn to take a look, he said, "hey! I remember you! You're the only one in that class that ever asked any questions. Thank you. You made that class better for me." So yeah, introduce yourself, ask questions and do the work. You'll be fine whether you have the sweetest professor in the world or the guy with an awful personality