All the characters that you recognise are that of J.k. Rowlings, the ones that you don't (Lily) and the plot are mine
Title: Deja Vu
Characters: Minerva McGonagall, James Sirius Potter
"No, Potter, I will not go out with you. Leave me alone for Merlin's sake." The shrill voice is heard long before it is seen. The girl's normally light blonde hair is a bright cherry red and her green eyes blazing. She is walking in front of a boy and is angrily muttering to herself.
"Come on Lily. Please. Just one date?" the boy runs in front of her bending on one knee and puts his hands in a begging position, so it makes him look like he is praying. He looks at her with hopeful eyes, flicking his black hair out of the way. Minerva McGonagall was struck with a strong sense of déjà vu. She has seen this scene played out before, in this very classroom.
"Potter. Leave me alone and go play with your broom." Minerva chuckled and sat back, content to watch these two fight until the start of lessons, a reminder of two other students who graced the class room with their presence many years ago. Those who were very much like these two students. The girl incredibly smart, and the boy incredibly arrogant. "Can you not get it in that thick head of yours, I. Do. Not. Want. To. Go. Out. With. You. At all, end of story. Stop bugging me."
"Please Lily. You don't have to marry me or anything; we can wait till we are older for that if you want." He says grinning. She scoff's and walks around him, making sure not to let him touch her, walking to her seat next to her friends. As soon as she sits down they start giggling and she glares at them, hitting one or two. He climbs to his feet and shrugs walking to the other side of the room to his own seat still looking at the girl. He then looks to his friends who are rolling their eyes, "She totally wants me."
Right at that moment the bell goes signalling the beginning of class everyone shuts up and looks towards the front of the classroom towards the elderly teacher who had been there decades. Minerva stands up and points he wand at the board and writing appears in curly handwriting.
"Copy the notes on the board and then try to transfigure the animals on your desk using the spell we were learning yesterday please." This set of instructions was followed by the rustling of paper and everyone grabbing their quills. A quiet murmur starts as people start talking to their friends next to them. Every one looking down at their parchment and every now and then bringing their heads up to read what was on the board.
Minerva sighs and leans back in her chair thinking back to the days before the war when Voldermort had only just started gathering follower's and Albus Dumbledore was still alive. The James Potter of that time had been trying to get a different Lily to go out with him, but other than that it was a strange occurrence of time, like history was repeating itself. But things were different now, Voldermort was dead, there was no war and everyone was - relatively - peaceful.