As is explained here,
Quote Quoting How long will it take to get my K visa?
For Form I-129F, Petition for Alien Fiancé(e), you can visit the USCIS website for the status of your petition.

Once your case has been received from NVC by the U.S. Embassy or Consulate that will process it, the length of time varies from case to case according to its circumstances. Some cases are delayed because applicants do not follow instructions carefully or supply incomplete information. (It is important to give us correct postal addresses and telephone numbers.) Some visa applications require further administrative processing, which takes additional time after the visa applicant's interview by a Consular Officer.
Five to eight months would not be unusual.