Is it bad luck to shop for baby early?

LaTosha • We're excited to welcome baby number 7!
So I'm almost 8 weeks, and after my 11th week ultrasound, I want to start stocking up on diapers, wipe, etc. for my little love. I ran this across my mom and she told me to at least wait until I reached the half way mark to start shopping because it was "bad luck". I laughed it off but then I became worried. Has anyone ever heard this before? I'm already worried about my baby sticking so people shouldn't say things like that.