Deferring ain't that easy...if it were, everyone would do it...
My school requires a first year to have a very compelling reason: a scholarly fellowship (Fullbright, Rhodes, Marshall, etc.), a 2 year stint in the Peace Corps, or something...well...rather negative (e.g. last year, a student was given a deferral, because his father passed away 1 month before the start of school)...
I'm not sure what the policy is like at your intended school, but I don't know of a one that allows deferral because a student wants to get married before matriculating or because a student wants to "enjoy being young."
The only way out I see is to be soooo poor that the fin aid office couldn't possibly cover you, i.e. have tremendous debts that require immediate payback -- by the way you sound, that probably isn't the case.
In any event, only start med school if you're ready for it. If not, tell your school your reasons for declining them and reapply when you're ready. Deferrals are VERY serious matters for all schools -- they invest a lot in you when they give you the admissions offer; they expect to see you there the following fall. Deferring after your second year is somewhat easier than deferring before you matriculate -- you can get an MPH or something; that way you'll have more time to do what you want and have a valid reason for your deferral (note: you can't start on any degree after the one you've last earned BEFORE you matriculate into your first year).
Good luck to you. I hope you make the choice that will be most comfortable.
[This message has been edited by dh (edited 12-18-1999).]