First, fiance visas are for people who intend to marry in the US. 9-11 months is average these days.
Second, marriage takes about 12 months as long as there are no problems. Permanent greencard may not come for a few years since initially most people are receiving a conditional card if the marriage is less than two years at the time of approval. You go speak with a good immigration lawyer to discuss the options in further depth.
Under the principles of comity your marriage should be accepted in the United States, if you decide to wait and instead file for a fiance visa, once he arrives to the US you can marry within 90 days which would be the term of his visa. The process to adjust would take in the United States about 5 months to be finalize. The term of processing your fiance visa depends on the consular post some are 9 to 12 months. The help of an attorney during the process would be very helpful
I agree with my colleagues.
(213) 394-4554 x0 Mr. Shusterman is a former INS Trial Attorney (1976-82) with over 35 years of immigration experience. His response to your question is general in nature, as not all the facts are known to him. You should retain an attorney experienced in immigration law to review all the facts in your case in order to receive advice specific to your case. Mr. Shusterman's statement above does not create an attorney/client relationship.