I don't know if my path was "messy", but I'm certainly a fairly late bloomer. Worked four years as an assistant at a 2A, where I felt (as you put it), woefully inadequate. Had such a bad time with a terrible principal my second year I very nearly left the profession. So glad I stuck around (I outlasted him).
I never took a band to UIL until my 5th year of teaching (then at a BBB Junior High - weird classification for sure). Generally got 3's (at least one 4) but this inner city school was where I really learned how to teach, and LOVED my kids. After four years there I moved to a rural school and have spent the past 21 years in the small classifications. Never got a sweepstakes until my 9th year of teaching, and have still gotten lots of 2's (and the occasional 3) with groups. Just how it goes.
However, along the way I've also gotten 3 State Marching medals (one is gold), lots of sweepstakes, a couple of top 5 Honor Band finishes, and an OPS win, so I think I'm pretty "successful" if you look at it that way. (I think I'm pretty "successful" because I've carved out a nice career being around wonderful small town kids and hopefully making an impact on their lives in some way.)
The longer you do this, the more you realize it ain't about the hardware or the ratings (but they are fun to get!)
Best of luck to you - I wish you a long and happy music career!