you are American by citizen , don't worry about any legal issues here in Doha, this is the bottom line. regarding traditions and clothing and other Islamic requirements they come down to your preference .no one will force you and no one will tight your freedom just because you converted. in fact no one will know you are a Muslim if you do not inform them! you got my point?
just go ahead with your quest and if this marriage what makes both of you happy then do it and turn off your ears. if it doesn't work for any reason you still can claim your self. my advice to you is not relevant to your marriage.
read Islam from your heart and you will find happiness and sanctuary. don't do it because you want to marry. because you can marry as you are a christian of you want to.

may god bless you and show you the right path.