I don't know why I started--I've always wanted to play the guitar--since I was a small child.

As to the how-As I wanted to play guitar--when I was 5 or 6 I got a toy plastic guitar for Christmas--but unlike most of them--this one had 6 strings and could actually be tuned.
Still it was a toy guitar, but a very good one. However it later broke, was repaired, and then broken again, so it was garbage.

Later, when I was asking for music lessons my parents started me on piano.
They found a teacher, got a piano and I took lessons for 3 years. For me it was a detour, as there was a promise of guitar lessons after some piano lessons. After the second year my teacher moved to another city and the new one for year three was not good. There was a new piano method that I learned from, and rather than build on my first two years, my teacher declared I had to start over--way to crush a kid! I still wanted to play guitar, but wasn't into lessons by this time. That summer i bought a cheap acoustic that was a waste of good plywood. I never bonded with it, and it is the only guitar I eve sold--for the same cheap price I paid for it.
The year of trying to teach myself was difficult as I was never sure if my guitar was tuned properly and if I was doing anything correctly, so I asked my parents for lessons, and I started on classical, getting a real good student model that Christmas--and then switching to an electric a couple of years later--I've kept playing and enjoying it.

I don't know why I wanted to, but I'm glad I did.

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It wasn't Willy-Nilly, it was at crows.