Don't feel comfortable going past 41 weeks in pregnancy

Alexis
Today I'm 39 weeks exactly. But no signs of labor. Only dilated a cm and still in the process of thinning out. Today my midwife talked to me a little about what's going to happen next week. I will be 40 weeks on the 20th and on the 21st I have my prenatal care appointment and a NST with it. But I know at 37 weeks your placenta starts to die... With that being said and because I'm naturally a spaz I don't feel comfortable going past her due date ecspecially 41 weeks... What should I do!?!?