If you would like to enter this field, there are several things on which it is important to focus:
--Developing your education to support the craft and the industry (improves your skills, knowledge and ability, and makes you more attractive to potential agencies and clients).
Reading of screenplays (100 minimum); the more the better. Focus on reading 'successful' screenplays. We are a big part of what we read. If you want to be able to recognize a good screenplay when you read it, you will need to have read enough so that your brain is programmed to intuitively detect and distinguish the successful plays from others that are not viable for further development.
--Becoming at least a student member of the Screen Actors Guild and/or Screen Writer's Guild. Attend at least one play a month, or more, if possible. Focus on one professional screenplay writer a month, and also, attend community theater, high school plays, etc. Watch TV plays as much as possible.
--Network with tradespeople by attending functions. At first you may not be invited, but you might consider crashing them or attend by paying the entry fee. You can even attend them by volunteering to be part of the staff. Anything you can do to attend cocktail parties, award ceremonies, (Emmys, etc) will be invaluable. Seek out internships in the field and a 'mentor' that will allow you to work with him/her to learn the trade.
Finally, if there is a Community Theater or College Theater group you can join, this would be advantageous. It's important to have sense of what it's like to be in theater. Take on the role of actor, stage manager, prop guy, a reader, etc., to get experience in various areas. Everything you experience in school, coupled with the other activities, will help create a personality and demeanor that will fit with being a screenplay agent. You would, so to speak, be immersed in the field/preparation for a couple of years, but when you emerge from your 'training' phase, you will have the ability and foundation to excel at the trade.
I wish you much good luck!