First off, Let me address an oppressive issue in our school system. Yes, you guessed it! Recorders! Schools hand out recorders as a test to see whether or not the pupils are interested in music. Recorders! They have a unique layout that isn't, to the best my knowledge, shared with any other instrument outside of its family. And they're so ludicrously boring. Don't get me wrong, they're great instruments, and there are many talented and wonderful pieces which fit well with the recorder family, but for a typical everyday school student, how could they be interested unless they're already into it?
I propose handing students penny whistles instead (unless they're worried about children hitting and stabbing themselves with metal instruments). Hear me out on this! Here are my reasons:
For one, they're cheap. Really cheap for a decent sound. Secondly, they share a common key signature. If you buy a whistle, chances are it's in the key of D, which is shared throughout many music types and music genres. Not only that, they also share the same scale as a lot of diatonic instruments. Starts on a D note and ends on a D note, following up the octaves by removing one finger at a time until you get to the 2nd D, which then is back to having all wholes covered. No weird fingering like recorders have.
Since whistles have have the same scale, they have a lot more in common with many other instruments, such as diatonic reed, violins, mandolins, cellos, and more. They all start on the first note of whichever key they are in, then go up the scale. If you can play a whistle, you can play a penny whistle. You can practically play all of them! This goes for violins too. A violin has four strings, G-D-A-E (low to high). The tuning is the same for mandolins and cellos. Violas however, use a different tuning: C-G-D-A, so they're the odd one (not to mention viola players). When only considering these few string instruments, guittars (yes, that's the correct spelling! Unless you're spanish) almost become the recorder of this handful of strung instruments. Diatonic reed instruments, i.e. melodeons, diatonic button accordions (same thing but have more than one row), anglo concertinas (anglos are usually G/C), (a lot of) harmonicas etc share the exact same note layout. However, with whistles, they're technically chromatic no matter what key it's in. If you have a whistle that's in the key of C, you have all the white notes and all the black ones by half covering the holes. So the key signatures are more for convenience and ease of use if that's the key you'll be playing in the most.
Chromatic instruments are a different story... Diatonic instruments only have one key per row. Melodeons only have one row, so they only have one key to offer. The same goes for whistles unless you play two at the same time. Or, if you're professional, use your vocal chords as a compliment. Diatonic button accordions generally have two rows. In England, the default keys are D/G. D on the outer row, G on the inner row. (If the rows were swapped, it would be a 'G/D'). You can get models with three rows, but these are almost chromatic, meaning you have all of the notes available to you. So a diatonic button accordion with four rows would be fully chromatic, making it a button accordion effectively. But that being said, these share the same system as piano accordions, having each button the same note whether push or pull. On diatonic button accordions and melodeons the starting note is on a push with every other note on the pull. Because all of the notes are available on chromatic instruments this means that note layouts vary widely. Take guittars for instance, though here I'm talking mainly about note arrangement and fingering, not chords. All instruments with a piano keyboard have, obviously, the same layout. Hurdy Gurdy's share this layout too! They started off only in the key of C originally, chromatic layouts have been around for more than long enough now though for this not to be significant. Take nyckelharpor ('nycelharpa' is singular while 'harpor' is plural) for instance. They're unusual aren't they? A miniature violin bow, keys (the things you press to make a noise this time) like instruments from the Hurdy Gurdy family but many more, a lot more in number, but just without the wheel mechanism. But oh! Are they beautiful!
You've probably guessed by now that I'm a folk musician... I have experience with a number of these instruments, couple that, with enough knowledge albeit visual, audial or just from reading, you can get a tune out of any instrument. It won't necessarily sound good at first unless you're already familiar with it. like, I play a whistle, so I know about air control. I play an anglo concertina and a diatonic button accordion, so I know about the layout of harmonicas. Just a quick up and down the scale and you're good to go.
But the elephant in the room is the understanding of it all. That part is up to you, and is also the part that determines whether or not instruments are for you. Getting an, or the understanding isn't something you learn, or find. It just happens. There is a story of a great violinist who was in an orchestra... couldn't for the life of him play a mandolin, which is bonkers because, other than a mando being plectrumed and the other being bowed, they're the same instrument. Everybody is different, everybody learns differently, everybody posesses different tastes, tallent and skill. Work out what yours are and use them how you see fit. Not how your teacher wants you to. And make sure you learn how to play by ear, or likely you'll be ruined later in life. Nobody wants someone who cannot play a dime without lugging tons of sheet music and a stand everywhere they go. 😊