I'm in a similar boat, Jason. There isn't really any definite way to determine if the school you've chosen is "good" or "bad," because, as others have mentioned, what works for one student might not work for another. But here are a few suggestions for you:
1. Find out what the school teaches in broad terms (e.g., basics, sparring, self-defense techniques, etc.) and see if those are things you want to learn. Another beginner here recently posted a question about sparring, because there is no adult sparring at her school; many people feel it is essential, some others do not. See if what the school teaches matches what you're looking for. If it doesn't, check out a different school in the same style, or a different style altogether.
2. See if you can observe a group class or two, preferably both a beginner class (like one you would be participating in) and an advanced class. Do the more advanced students move well? I realize that, as a beginner, you might not be able to tell if they move "correctly," but you'll probably get a sense of whether or not they move the way you decided that you wanted to move when you decided to look into a martial arts school.
3. Visit more than one school with those questions in mind.
I think it's great that you're asking questions early. In my case, I signed up at a "kenpo" school, and then learned that not all kenpo schools teach the same material. It turns out that my school teaches an older version of what Parker taught, tempered slightly with some Tracy material. After learning a lot by reading the kenpo forums here, I've decided that, for now at least, I'm happy where I am.
Good luck!
Rich