To what I've experienced flying from AEP if there are too many flinghts departing on that time, you'll probably have problems passing security as there is only one person controlling every boarding pass and passport, but according to the airports website your flight is the first to depart from that day so you'll probably have no problems with that, although I recommend you to be there at the time they say you to be. If you don't have to drop baggage off you may be later but not that much.

Have a nice trip