This can happen with Autoflowers. I’ve seen some show pistols after the first week, which is not cool at all.
This varies greatly with genetics and environmental stressors. You can’t do anything about it with the genetic side but stress can be limited with steady light, temp, humidity and airflow for your environment. Also defoliation, topping or training are forms of stress that could cause the plant to begin flower.
On the plus side, it looks like your girl is doing very well so far so you still should get a decent amount out of it. Some autos can nearly triple in size during the first two weeks of slower.
Hope this helps.