An auto, unlike reg. and fem., initiates flowering on its own when it's ready. So far, so good; if the conditions are right, it can even happen earlier, especially if you have a strain that generally requires fewer weeks.
Yield can be roughly estimated with a rule of thumb: [Number of watts of your lamp(s)] x [Experience value]
The experience value usually lies between 0.5-1.5. (Depending on the methods and conditions in place)
Count on a value starting from 0.7 if this is your first grow. In the worst case, you'll get more harvests ^^
A quick example: Lamp with 300W and some experience: [300W] x [0.85] = ~255g
However, since we're dealing with a plant and not a robot, this can only be taken as a rough guideline because there are simply too many influencing factors.
The main thing is that growing is fun and you have your own clean result. Happy Growing 👽