Betta Fish: my “baby female betta”

I bought my buddy back in May at petco. When I bought him I thought he way a lady, because that’s what the container I bought him in said. Now that it’s been a couple months and there’s clearly been some major changes, I was wondering if anyone knew what kind of betta he is. Considering I only paid 4 dollars for a baby female betta, I think I got a pretty good deal on him!
The first three pictures were taken just now, and the fourth one was taken when I upgraded him from the shrimp tank to the 10 gallon tank. He used to be so tiny.