FWIW:
Enlist as an infantryman, then excel and strive to be the best Marine and best teammate you can be. There is no way, as far as I know right now, to enlist with any kind of Recon guarantee like the Army does for Ranger Battalions.
Do a couple of floats and when you're in outstanding shape and can land nav with your eyes closed and one foot tied behind your back, go to a Recon tryout.
You will have to score a first class PFT, then do the obstacle course for time (not sure of the actual time cutoff), then do a ten mile hump with a ruck on your back. Then you head to the pool. If you pass all that, there will be an interview with the Sergeant Major of the unit you're trying out for. Then and only then will you have to worry about getting permission from your CO.
For now, get into your unit and find a fireteam or squad leader who is really locked on and do what he does, how he does it. Start carrying yourself like a Corporal when you're a Lance Corporal and you will be golden.
Don't get in fights; don't get a DUI; don't write bad checks; don't get a girl pregnant.