You're talking about an english teacher, not a physics teacher.
I'm gonna hazard a guess that your teacher is leaning more in a kurt vonnegut direction than an albert einstein direction.
In Slaughterhouse Five, as it says, billy pilgrim has come unstuck in time, and from moment to moment finds himself living as a prisoner of war in WWII, or married and raising kids, or any number of other things. This causes him a great deal of distress until he is abducted by a race of 4th dimensional aliens (Tralfamadorians) who explain to him that linear time is just a perception that human beings have - that all moments in time exist equally, always have existed, and always will exist. Tralfamadorians see the whole of time at once, and are slightly confused by the concept of linear time. They also insist that humans are the only race they've even heard of that have a concept of free will.
It's an interesting take on predetermination but you can't read too much into it. The book is semiautobiographical - Vonnegut was a prisoner of war and survived the bombing of dresden - which was so bad that the pavement in the streets boiled. He was then forced at gunpoint to collect the charred bodies of the dead.
He suffered from rather severe post-traumatic stress. In one of his essays, he explains that when he was living in Cape Cod and working as a salesman for a Saab dealership, he had two big black labrador dogs. He said that every day, he'd get home from work and wrestle with the dogs for a while, and it was great.
One day he came home and his son said "Dad, you always play with the dogs but you never play with me" - so he wrestled with his son for an hour, and it was great - he said it was just like wrestling with the dogs. And he never did it again.
What Vonnegut is saying - and it gets explained further in Sirens of Titan - is that things just happen. Life is filled with good moments and bad moments and all of these moments, objectively, are both meaningless and inevitable. The way to survive - at least if you're billy pilgrim - is to focus on the good moments and ignore the bad moments.
English teachers are often bad at physics, and fair at philosophy.