I suggest speaking to an attorney before doing anything.
You don't say in what status you entered thee U.S. on the I-94. If you entered as a visitor, you may have a problem.
Entering as a visitor means representing that your intent is only to visit - to remain here temporarily and then to return to your home abroad. Marrying a citizen and applying to remain is viewed as inconsistent with this intent. Dates of entry and marriage will be visible from the required paperwork, and there are legal presumptions in place leading to a determination of fraudulent entry when such a marriage occurs within a certain period after entry as a visitor.(there are 30- and 60-day periods built into the law for this).
There is a separate fiance visa intended for use when someone enters planning to marry a citizen.
Speak with a lawyer for advice on this - and do it before actually getting married. There are several possible options here.
Hi. YES the attorney's above advise about the B visa not being a dual intent visa is right on. You need to be very careful with this since your dates are so close (visa expiring and marriage date). There are visas that have dual intent...in which case this would not be an issue..however, I have a feeling that you entered the US on a B visa. Good Luck.