Green cheeked conure regurgitating

My green cheek conure yoshi has been regurgitating seed for me. He is only 4 months old and I read somewhere that that's how you tell the difference between male and female but I also read that they won't start doing that until they reach maturity. He just started it yesterday and only seems to do it in the evening. And I've only had him for a week. I just want to make sure this is normal. Thank you from a worried new conure parrot owner :)