Well, of course the MC is telling his story and its kinda a "flashback". Read the introduction of the game again... "let me tell you what happened" thats the sentence you see before the game really starts.
Overall, i think he is telling us about his first year on college and after the first year is done, the game will end with a view on the present and a little ahead in the future maybe, based on the choices of course.
I had a different approach in mind too... like the movie american beauty. Maybe, and its a BIG maybe... the MC will die at the end and is just telling his sotry of his last year alive... but i have no "proof" for that, just a gut feeling... many many books, movies, stories starting like this where the protagonist tells a already happened story, the protagonist gonna die, is already dead, or facing death.
Those phrases where he talks like everything already happened and he is just telling his story are at several points of the game.
Well it is certain though that the MC is just the storyteller about his time at college and everything we see already lies in the "past"
Doesnt really matter much for the time being. But its already a heads up to how the game ending can be made.
And because its a story of the past, it does explain more that we can see so many scenes without the MC in it... cause in the end, he knows those things after everything happened the way it does.
This way to tell a story which already happened is a easy way for an author to go over plotholes especially about things the protagonist cant know about if he wasnt there... but if it all lies in the past, of course somebody could have told him after all, or something.
Overall DPC isnt really following those approach though... sometimes he jump to a phrasing where you can assume that everything already happened, but most of the time telling the story like nobody knows shit. If you tell a story like that, sometimes a "narrator" is needed. But this is missing here. Mqaybe cause DPC doesnt care about it, or he want to set up the illusion everything is happening just now, but if he wanted to create this illusion, he shouldnt let the MC talk the way he did in your screenshot for example, and thats not the only time he does that. But we always should keep in mind... DPC is not really a great author. Not even close.