My last job, Gorilla Girl was planted in 5.5 pots. As for your decision, knowing that the strain you’re growing is autoflowering, and based on my experience with them, you’ve made the best choice. Autoflowering strains are genetics that are crossed with ruderalis... I won’t bore you with details, what I mean is that their growth cycle is destined to be just a few weeks, regardless of the climatic conditions, which I think is a good choice because for root formation in a short time, it’s one of the best sizes. If we were talking about feminized or regular seeds, it would be a different story. But in your case, luxury, and it looks quite nice, I hope it stays that way and soon the pre-flowers will show up.