I had to learn accordeon when ten years of age. I started with a small one, and when I grew bigger I got a real great one with 120 basses.
For four years I got a solid theoretical basis which is still valid today. I think it is the right instrument to teach music theory best with all its ramifications, and smaller specimens are easy to transport.
Recorders are more for melodies alone; to get harmonies you have to play in groups from bass recorders to the very little pipe (an octave above the soprano). They are easy to play and give the beginner soon a feeling for achievement. But alas! Most of the kids stop playing the recorders when leaving school! I carried a sopranino (aka "battle recorder") in the breast pocket of my BDU. But my younger daughter (the beautiful singer) still plays the recorder, and well. She surprised me playing some of my favourite songs at my 60th birthday with the help of a friend playing the 2nd parts.
The training with the accordeon made my tender artist fingers flexible and apt to change to guitar which is also a good instrument to start. I also changed to guitar because of the wonderful sound and the renaissance pieces I taught my self to pluck.