What Paul McCartney 's first instrument?
There had always been an piano in his home but Paul's first instrument was a trumpet. This was bought for his fourteenth birthday by his father, who hoped it would help distract him after the recent death of his mother.
Paul also had a few lessons at this point. It seems they introduced him to at least some basic musical theory
I persevered with the trumpet for a while. I learnt ‘The Saints’, which I can still play in C. I learnt my C scale, and a couple of things.
Though Paul ‘loved’ trumpet, there were practical problems.
...I realised that I wasn’t going to be able to sing with this thing stuck in my mouth, so I asked my dad if he’d mind if I swapped it for a guitar, which also fascinated me. He didn’t, and I traded my trumpet in for an acoustic guitar, a Zenith, which I still have.