So, it took me 5 weeks after taking delivery of my model s to begin receiving updates.
Once they started, new ones come almost as soon as released.
Some speculate that 5 week period is intentional to let you get used to the car before switching things up.
Personally I think that it just takes 5 weeks for a newly activated VIN to percolate through the update queue.
But I predict that 5 weeks from when you took delivery (or thereabouts) you will get the first of many exciting notifications from your Tesla app!