Can Cm1develop later in life?

I was wondering if Chiari could develop years later. I had an MRI of my brain and cervicle back in 2007. They both came out with normal findings . Then I had a brain MRI in October and they found CM1 at7mm. I’ve never had a spinal procedure so I’m baffled at how it showed up. From what I read it’s a something acquired since birth. Has this happened to anyone else?

Sometimes I think that the general consensus that Chiari is present at birth needs to be changed. I had an MRI as a child with no evidence of Chiari. I did not have any symptoms until my late teens - in hind sight after a car accident or two and bumps on the noggin through sports. I also have generally lax ligaments and am a flexible women. My theory is that time and life events can promote that all dreaded brain sag and the symptoms that go with it. Other wise, lots of Chiarians have had no symptoms until they reach adulthood. Maybe I should change the model to two sets of CHiari presentation - one is congenital and one is acquired. Of course, this is based on no readings, just my understanding of anatomy, physics, and symptoms presentations.

Any other thoughts?