You all can say, "AA doesn't make this clear", "AA is so bad", etc. etc. But it doesn't change the fact that checking luggage is part of the check in process and its quite clear on the website that the check in process has to be completed at least 45 minutes prior to departure. Just because you have checked in online doesn't exempt you from check in time requirements.

Don't blame the airline for not getting to the ticket counter in enough time.