Royvanessa

The form you receive is the acceptance of your petition. Is called NOA1 or Notice Of Action I-797. And is your receipt too. In there you find, case number that have to start with the 3 letters of your service center, your priority date, beneficiary information, your information and the amount of money you paid for the filling of your petition. Now you're in the waiting game of waiting for NOA2 this is the official approval of your petition. You have to find which service center you're at and then go to uscis.gov and find the approximate time  for adjudication of I-130 and like that you will have some knowledge when you can get approved.

It is taking longer than 2 or 3 weeks, I believe more like 4-6 weeks, to get the NVC case number.  Call them 603-334-0700 Monday - Friday 9am - 9pm.

NEVER make concrete decisions like that until the visa is physically in your hands. Even if they tell you you are approved many things can happen. AP is open ended. You could be in AP for months (although I hope it doesn't take that long) but we have certainly seen it often where AP is longer than anticipated.
 
There are even cases where the wrong information was printed on the visa so the applicant had to send it back which further delayed the process.
 
You should have really waited until you received the visa in person and can physically check it for accuracy. It is advised by us and US immigration not to do these type of things until then.