This timeline intrigued me. It struck me as illogical as it tells us that the earliest instruments were flutes. My Grove Dictionary says there is a lot of controversy on this subject. I always supposed some sort of rudimentary drum, but thinking it through now that can't be right either. The answer is clear and can't be in doubt: The first musical instrument had to be the voice. Cheers and thanks for this stimulating post.
Piano is just 300 years old? There's more.
I've never seen the evolution of musical instruments referred to or even thought about it myself. Here's the timeline. Enjoy.