Look at you, bringing this thread back from the dead.
First of all, even if we take what you’re saying at face value, how does it being an original text in any way prove that its contents are true? If I made up a completely original story today about a stuffed animal that eats pickles and poops diamonds, would that mean that such a thing exists?
Secondly, we can’t take what you’re said at face value because Qur’anic and Muslim scholars are very divided about the origins of the Quran.
People often find a lot of change in their thirties (I sure did). I don’t know if it’s metabolism slowing down or just life getting more crowded and sedentary for so many of us. I was super skinny all my life - in my teens I had to force myself to eat until I was uncomfortably full just to stay even - but in my thirties I got a little belly. I also lost most of my hair in my mid twenties, so I looked like a different person between 20 and 30.