>>102757718CVID in and of itself does not actively harm the body like an autoimmune disease.
Rather, it's a catalyst for external diseases to take hold (easier than normal) and do damage (more than normal).
As such, a CVID patient is born, in practical terms, about as healthy as any other person. Their condition may then worsen over time due to their lacking immune system.
A properly-treated CVID patient can live a normal life, more or less. The problem with Mouse is that her family couldn't afford proper treatment, which led to multiple severe illnesses.
Mouse lived a reasonably normal life up through high school. She got sick a lot as a kid but in her teen years there was a period where she rarely got sick at all (according to the IDF in her podcast episode, this is actually common with CVID patients). Around the time she reached adulthood her condition sharply worsened and she had to drop out of school.
So when you hear her tell a story that makes you think "but wait I thought she couldn't X," it's a story from the time that she could.
It ain't that complicated.