Practical Travel Safety Issues - GE card time to mail

I have my GE interview this Friday afternoon at the Atlanta Port Office--whoopee!

From the time the interview is over, how long will it be until I get the card in the mail?

Also, if I buy an airline ticket before I get the card in the mail, will I still be able to use the GE card to take advantage of TSA PreCheck at participating airports?

Thanks!

Addendum: My interview notice has the following at the bottom:

Special Instructions: Atlanta has two enrollment centers. The port location at 157 Tradeport Drive, Suite C will benefit passengers that wish to enroll but do not have plans to fly on the day of your appointment. If you plan to fly as part of your enrollment process, the airport would be your best choice. If you are not planning to fly but wish to enroll at the airport, you will need to print out your schedule notice to present to the TSA Officials at the airport since you will not have a boarding pass. Our enrollment center is located on concourse “E”.

Translation: "Save this page and all the images on it. If anyone ever wants to get into ATL's 'sterile' area in the future, change the interview date, time, and location with a text editor, print it again, and present it to the TDC. There's no name on the page, so anyone can do this."

Hopefully, the terrorists will never find out about this loophole and exploit it to gain access to the airside Pizza Hut.

I think I got mine within a week. You don't need the card to fly, just the passport. They activate the passport chip so the ge machine will recognize it. They tell you that it might take up to a week for the system to have you in it, but within 24 hours my account was updated, just check your ge account.
You have 30 days to activate your card from the time you get it, I think