They're cooking this lady alive about being 39 weeks pregnant, is that not normal?

I didn't give birth until I was like 42 weeks pregnant. And I just saw this video where this girl was like, I'm 39 weeks pregnant, I'm gonna let my body go into labor naturally. Like my body is just fine, knows how to work itself. And people were in the comments cooking her up saying like 39 weeks is too long and you're gonna overcook your baby and all this extra stuff. I'm like, um, I went almost 42 weeks and I'm perfectly fine. My child is perfectly fine. So where did this like misconception come from where if you go past like a certain amount of weeks, then something's wrong with you? Like I'm confused. Like 40 weeks is actually the norm and my doctor was not worried about me going 42 weeks. I'm the one who got induced myself. I like told them I wanted to get induced because I was tired of being pregnant. So what's wrong with going longer? I don't understand that. I guess I'm so confused. Like someone please explain this to me.