Your priority date may be different from what you expected. The most common reason is a delay in mail processing by USCIS.
As a general rule, however, your priority date is determined in one of two possible ways.
If you filed for your green card as a family member or if you filed under one of the employment-based categories that do not require a labor certificate your priority date will be the date your petition was received by the United States Citizenship and Immigration Services (USCIS)
If you filed for your green card based upon one of the employment-based categories that do require a labor certificate your priority date will be the date that your labor certification application was received by the United States Department of Labor.
To find your officially designated priority date you would look at Form I-797 Notice of Action sent to you by USCIS. If your case was approved by USCIS you should have received at least two separate I-797s. The first acts as your filing receipt and the second acts as your approval.
Once you determine your priority date you would then check the Department of State Visa Bulletin in order to determine your place in line.
The official State Department Visa Bulletin can be found at :