Yeah, you're gonna get a lower yield..
You topped while it was showing signs of preflowering.
It's unfortunate, but you'll learn from it for the next time. ^_^
If you want to top, start with photos. Once you've gotten the hang of it, you can try your luck with autos. There's quite a setback in growth, if you do a bad job topping..
- A general rule worth following if topping autos, don't do it after the third week.