A visa allows your fiance to enter the country. If the Visa expires in 6 months then she would need to enter the country before that six months is up. It has nothing at all to do with the 90 days to marry. That has to do with her date of entry. You have 90 days from the date of entry to get married whether or not she waits six months to enter the US or enters immediately.. It is 90 days after the date of entry..
Once married the Visa has little value unless you need to prove she entered the country legally. That should not come up under ordinary circumstances but hold onto it regardless. It will be stapled in her passport. The next step after marriage is your adjustment of status.. But, take things one at a time.. Get the visa.. enter the country.. get married.. adjust status..
Tom and Novie got a reaction from TBoneTX in Length of Validity of K1 Visa