Yes...it's pretty much a shot in the dark if you go at it on your own.
You may narrow it down to what you would like to learn, but once you start, you may find that it isn't what you thought it would be.
On the other hand, some styles may not appeal to you on the surface, but you may find that you like it once you get started.
I guess keeping an open mind is the key.
For me, getting started was the biggest step. With no previous martial arts experience to speak of, I felt that doing something was better than doing nothing at all, and I chose the school that I felt the most comfortable with.
I may decide to switch up in the future and try a different style, and not being bound by a contract gives me the financial freedom to make that choice if I feel the need, but as for now, as a beginner, I look foward to classes, and find myself remembering many of the techniques that we practice.
Insert profound martial arts quotes or tough guy phrases here.