You are overthinking this.

Your science notebook should be a reliable uneditable record of your day to day observations. As long as you date entries and don't cross anything out or erase anything it does not really matter how the pages are numbered.

You could write a comment in your the book today that on June 10 you discovered you have misnumbered pages but that none of your entries (past or future) will depend on the page numbering.

You have nothing to worry about. Just do the science as best you can.

You are overthinking this.

Your science notebook should be a reliable uneditable record of your day to day observations. As long as you date entries and don't cross anything out or erase anything it does not really matter how the pages are numbered.

You could write a comment in your the book today that on June 10 you discovered you have misnumbered pages but that none of your entries (past or future) will depend on the page numbering.

You have nothing to worry about. Just do the science as best you can.

Edit in response to comments, many of which are concerned with patent legalities. I think they are not central (partcularly for a science fair project).

The point of the uneditable science notebook is primarily to keep you scientifically honest and able to demonstrate that honesty. It records your false starts as well as your good insights. It makes it impossible (at least in principle) to ignore data that does not support your theories.