It's okay—and good—to change your mind
A direct path to failure is obsessive compliance with the human bias for consistency. It’s perfectly acceptable to change your mind later if you’ve come across new information, or, come to understand something differently than when you first started (e.g., the scope or cost of a project). Don’t box yourself into a situation that you know to be harmful just to remain consistent with what you said in the past.
Get comfortable with changing your mind and the sometimes inevitable frustration that may cause others. To buffer these situations, make your reasoning clear so others don’t get the feeling of having the “rug pulled out from under them.”