GC priority date is current (March 2006) but no updates on case

[shargedu]

Hello everyone,

This is my first post on any public form so please bear with me. My priority date was March 2006, and on August 2017 our case history status changed to the following "We received your Form I-485, Application to Register Permanent Residence or to Adjust Status, and we are working on your case. You will be notified by mail when a decision is made, or if the office needs something from you."

The next step section says "We will assign your case to an officer. We will review your case and mail you our decision. If we need more information, we will notify you. "

My Green card was filed under the EB3 category.

Here is my question:

1. How much time is it taking after the priority date becomes current? Is this waiting period normal?
2. How would I come to know if there is an interview scheduled? Currently, I am checking my status on this website (https://egov.uscis.gov/casestatus/landing.do)
3. Is there something I can do to find out the status or why it has not moved?

Any suggestion and help would be hugely appreciated.

Thanks in advance.