Hi Estrella0798,
Great question! Generally, we advise most applicants against applying as late as Round 3, because by then the majority of slots in top MBA programs have already been allocated. There are some exceptions, such as for military applicants, but otherwise it's usually a better strategy to wait for the following cycle and apply in Round 1 or 2.
If you have all your ducks in a row, it's smart to apply in Round 1, because it shows the AdCom that you're super prepared and super interested in their school. However, applying in Round 2 is perfectly fine as well, especially if you need additional time to work on your essays, take (or re-take) the GMAT, angle for a promotion at work, etc. You can also spread out your applications between Rounds 1 and 2 if you're applying to multiple schools so that you have more time to work on each application.
I hope this helps! Best of luck!
Doris