My pool date is 20 March and I have an e-mail from HR saying that I will be in the next confirmed class. The last I heard, they expect that to start on the 1st of August, but they've been very hit and miss on predicting class dates.
If you interviewed with a type, your pool date is your interview date.
If you interviewed without a type, your pool date is the day you finished your type.
My latest rumor is one class in July starting on the 18th and three classes in August.