I'm thinking it's "autoflower" that's the problem. I'm going to buy regular seeds, non-auto. They have a way of guaranteeing that most or all of them result in 'female' plants. They're still stupidly expensive. I know I can get like 500 flowers in trays to all come into bloom at the same time. I do that every year. I should be able to manage this. That plant's only 5" tall and it's flowering. It's probably not getting much bigger.
Yeah, that's odd that it didn't grow more. I mean some are bred to be compact but not that compact.
How many hrs of light are you giving them a day? I am sure you are feeding n watering them enough, are they getting air?