As a Veteran Marine myself I would recommend that you completely pay attention to what you are told by your recruiter, and follow that information up with your own research. A recruiter, no matter what he says, is just looking to get you to sign up and ship to Boot.
Like Chief Dino said, assure the MOS you choose is the one you WANT (if you don't pick before shipping you'll be "open contract" and the Corps will place you where they need you).
At the end of the day what you put into your service is what you will get out of it.
As a former Marine I agree with the other comments. I would also suggest you play "hard to get" go in ask the questions you have and then tell them you want to go home and think about it. They will definitely be back in contact with you. Check on the best offers they have. I missed a $3,000.00 signing bonus 20 plus years ago because I just signed up without asking more questions.
Get the best offers from the other branches of service even if you are serious about being a Marine. Make sure you don't pass up something else. But remember, the title, "United States Marine" is earned, not given. You are in the Navy, in the Army, in the Air Force, But once you graduate from Boot Camp you ARE a MARINE and the change is forever. That is not just a recruiting slogan. You will always have other people give you more respect than those around you. I can't tell you how many times I have heard someone say, "I almost went into the Marines but.....(insert various excuses here)"
If you are interested in LAV's you have to be able to swim better than most. If you can't swim well enough it will void your contract and they will send you where they need you. LAV's are also very cramped spaces. If you are claustrophobic it is not for you.
You need to remember that all contracts have certain conditions that you have to meet. They will sign you up to be anything but if you fail the MOS School or can't meet any special requirements that MOS has (you are color blind, can't get the required security clearance, etc.) then you are not in compliance with your part of the contract and they can send you where they want.
Regardless of what MOS you end up with, if you are a Marine it will open a lot of doors and prepare you for a lot of things later on in life. When you say I am a Marine, it means something. Especially to all of us that are also Marines.
I have 4 college degrees including a Masters degree but the most important accomplishment in my life is the title Marine I earned on September 6, 1985.
I wish you the best.
I can't tell you how many times I have heard someone say, "I almost went into the Marines but.....(insert various excuses here)"
Like....I realized my intelligence level was beyond that of a termite and decided to be Navy instead?