Can you please anyone explain what I got email from NVC below. Why they are taking this much of time for me


"The National Visa Center has received all documentation necessary to complete pre-processing
of your case. As soon as an interview date has been scheduled, the applicant, petitioner
and attorney (if applicable) will be notified.

The applicant should NOT make any travel arrangements, sell property, or give up employment
until the US Embassy or Consulate General has issued a visa."