You said that you think you would prefer Area Control. On what do you base that, given that you know little about the job at present? Keep an open mind for the time being - your ideas may change when you learn more.
As others have suggested, try to make some visits to ATC units and get some background knowledge before you make a decision in the years to come. It's an immensely interesting and complex job and, at your stage, there is not much to choose between Area and Approach control. Or perhaps you mean the difference between Tower and Radar? THere are many facets to the job so do find out what you can as this will stand you in good stead when it comes to interviews and selection tests.
Controllers are required to meet similar medical requirements to airline pilots. If you were accepted for training you would have to undergo a fairly rigorous medical. If you subsequently became a controller you would have to undergo regular medicals to maintain your ATC licence. Don't worry too much about that yet - if you're an average fit young person you shouldn't have a problem. If you smoke, DON'T!
Best of luck and if I can help with any technical questions don't hesitate to PM me..