I am an author whose work you probably know pretty well - I wrote the Gospel that you call “the Gospel of Luke”, AND I wrote an early history of the church that you call “The Acts of the Apostles”, or often just “the book of Acts”.
You will notice in the book of Acts that some of the time I write to you about what some of the other disciples did, that I heard about from them, and sometimes I write about things I saw and participated in myself.
Jesus has been empowered by his baptism, or by the experience of his baptism, and it is really time to start his ministry.
He returns to Galilee and on to Nazareth where he had grown up. There, he goes to the synagogue, the place for worship and religious instruction. He clearly appears to be a teacher - so on this day, the Sabbath, it is time for worship. He does not choose the scripture - the scroll of Isaiah is handed to him.
We spend a fair bit of time on endings.
Graduations - and if we want to spin that, and say it is really about stepping forward into a larger world, remember the French expression: balle des finisants - it is clearly about ending
There is no such celebration when one starts school, beyond perhaps a special breakfast or supper with the family.