I change the requirements of my personal projects all the time.

Once I get a prototype working I get lots of ideas of how to improve things. I also see that some of my initial plans did not work I out as I envisioned and have to iterate on them.

If I can't get the requirements right on my own projects, then I have no expectations that others could do so either.

Have the expectation that requirements are wrong on any project. It is better to embrace that these will change rather than try to fight them.