I want to become an actor?

Continue with any acting/theater your school has to offer, but if you would like to use your skills for film there is no substitute for auditioning and getting on a set. Many colleges and independent filmmakers advertise on social media and craigslist for actors looking for experience.(Always be accompanied by someone and in a public place if at all possible when meeting someone online, and if they list a production company name, do some research to make sure they are legitimate).
In film, your theater experience will help, but you must remember that you are not projecting for a large audience, but a camera that picks up every subtle expression. Subtelty is key. Don't be afraid of the camera, it's your friend. Don't overthink it, know your lines and listen carefully to the director: The director is the boss. When you get more experience you can ask more questions and be more of an equal, but at first, do what you're told except when you fear doing what you're told might get you injured (that's rare, but it does happen).

Once you have a few projects completed, you take your best scenes from those projects and edit them or have them edited into a demo reel. You submit the demo reel to an agency to see if they would like to represent you.NO reputable agency (at least in America) will charge you to represent you. They only take a percentage of the money you have earned from projects (commercials, films, industrial training films, etc.) you have worked on.Never give them money up front before you have auditioned or been booked on a project that they found for you.
Acting is a very competitive, subjective and superficial business. Don't get discouraged if you don't get a lot of roles you audition for. The best actors out there (those of us who are working but not famous) only book about 20% of the roles we audition for. When you are not auditioning or looking for auditions,read as much as you can, watch what actors you admire do on screen (Hint: Don't blink. Keep your eyes open as much as possible), as well as observing normal people in real life for their mannerisms and habits. Roles will come if you stick with it and learn something new from each audition and each project. "Break a leg!".

Networking is the real key in how to get started in film. You must expand your network. If you do not have a network, start small and then begin to move up