Is taking a Theatre class the best way to learn how to become an Actress?

I am currently taking an Acting workshop class for the summer and I was wondering if these types of Theater classes are what I should be taking if I want to become an Actress. I realized while taking this class that there is a difference between being a part of the Theatre world and the Acting world. I would like to be in a couple of commercials along with possibly gaining some small parts in movies in the future but am I starting where I should? I am a beginning Adult actress so all of this is new to me. Thanks for all of your helpful answers.

The short answer is yes. With a foundation in theater you can move on to a foundation in Shakespeare, you can train in Improv which will help you when it comes to commercials and you can take some sort of on camera acting course. The more training you have, the more skills you will possess, the more value you bring to the table as an actor.