When will I know which gate to go to?

I'm flying through Delta Airlines and there is exactly three weeks until I go on vacation. I went a few years ago through Southwest and it told me right away which terminal and gate i needed to be at so that I could print out my maps so I didn't get lost (I was only thirteen at the time and am now 17). I have my itinerary online so when will it tell me the information I need to know? Is it normal for it to not tell me right now? Or will I only know when I get to the airport and get my actual ticket?