Emily wasn't dx'ed until age 7, due at least in part I am sure, on the dr's part, to not having serious respiratory illness when younger. As a baby/toddler she was healthier than my middle son- who we know doesn't have cf. She did have bronchitis once and needed a few weeks of abx for that but recovered without problems; we had no idea she had cf so she wasn't getting cpt or anything. As a preschooler, secondary infections became much more frequent but the primary fallout was severe weight-loss, not respiratory complication.
So, lung issues were not really bad until the year before her cf dx (age 6 onward) when she got bug after bug, and never recovered inbetween, culminating in her first pneumonia about 8mo before her cf dx. Things 'changed' then for her and she was sick in a way she'd never been before. Had we known it was cf we would have handled it so much better, of course, but that was when things changed for her from run of the mill illness that any of my kids could have had, to illness complicated by cf-related lung issues. Prior to that the problems I'd been trying for several years to get answered were related to growth failure>> which as we learned, were caused by a combination of PI and so many of her resources going to support lung function when she was sick.