Like others; understanding music theory is a tool, so I am starting there
Starting piano lessons at 7
Starting Trumpet at 9
Learning Bass much later (by then I could read well, the challenge was interpreting it to the frets)
Then moving to guitar much later

Every other tool I use benefits from my learning to play those instruments first .. and (for me) in that order

Piano helped visualize how to read to begin with
Then trumpet made me learn to transpose
Bass was kinda easy after I learned the previous ones, but taught me how to use a basic fret board (one note at a time)

Guitar was/is ridiculously hard; I visualize notes on the piano keyboard instinctively, so then have to transpose them to the guitar fret board after 'reading' it in my head first
//For me, learning guitar first would make learning theory a lot harder in the beginning

FWIW I can work with other musicians much better because of learning theory how I did
So I consider that my most useful music tool

I do not work here, but the benefits are still awesome
Make your sound your own!