mine just started poking out a few weeks and I'm 32 wks but it's just a half inny and half outty! With my first daughter it never popped out till 2 days before I had her. So my family always says she ain't done cooking. My timer hasn't popped yet. Everyone is different, along with every pregnancy. Good luck!
There's no telling until your ultrasound. I'm 39 weeks and my belly button hasn't popped out. It's very stretched, but not popped out. Everyone's different.
My sister is actually convinced its twins but I didn't hear two heartbeats....twins run in the family but no one has had them for about 8 years. I dunno my sister mom and hubby noticed it!
I'm 15 weeks with my 2nd, and showing quite a bit (but again, this is my 2nd, you show earlier), but still verrry low. I didn't get a pushed out belly button until 30+ weeks with my son. I don't think any belly button changes are caused from pregnancy at this stage, because the baby is still a little ways below the belly button.
It can happen at any time during pregnancy really...the top of mine was just like yours when I was 16weeks...I'm now 28+5 and the rest of it has just came out lol.
My belly button didn't pop out until I was 22 weeks. Maybe your having twins? Or could be carrying different then most women.