Paul McCartney met John Lennon for the 1st time on July 6, 1957. Lennon and his teenage skiffle band, The Quarrymen, were playing a Liverpool church social. After Paul's friend introduced him to the band. The 15-year old McCartney was able to show John guitar chords (John had only learned banjo chords from his mother.) Later, the band discussed if they should let this new kid join. But it wasn't until two weeks later when Pete Shotten, John's best friend, and Quarryman, ran into McCartney on his bike and approached him. The way Len Garry (another original Quarryman who was at their original meeting and whom I met) described it to me: Paul thought for a cool minute and then replied, ”Well, all right", and just nonchalantly rode away. Neither John nor Paul wanted to admit to the other directly, they liked and needed each other. And that was the beginning of one of the most fruitful songwriting and musical partnerships in history and would go on to change popular music and the whole culture.
Below John and Paul both describe that fateful day they met:
https://youtu.be/r_2f_UpTz24
Paul meets John (from film, “Nowhere Man.”:
https://youtu.be/QByhh5SlRpY