What is bodily autonomy? Most crimes are committed with the body in some form or another. What if I stab a knife in the air and somebody happens to be standing there? Thus it seems that the limit of my bodily autonomy ends where another person's rights begin.

The thing is that a lot of people think that a fetus is a person with rights. If a fetus is a person with rights then bodily autonomy doesn't quite apply. The bodily autonomy angle seems more of an escape hatch to sidestep the subjective and unsolvable issue of whether or not fetuses are people and have rights.

I'm pro-choice btw

Put simply: the right to decide what goes into and comes out of your body.

Your knife example has nothing to do with your bodily autonomy. It’s why you can’t be forced to donate a kidney or why you can choose to get a vasectomy.