Definitely get the free trial first! Most schools/training centers offer that so you can get a taste of what training there is like (in the one I train in, they offer an entire trial week, but you should get offered at least one trial lesson or class in the place you want to sign up).

In that way you can test if the environment, quality, style and focus of the training are right for you. Also, pay attention to the behavior of the people you are training with, and don't be shy to ask them questions about the place and if they would recommend joining in. Good luck!