American High School?

Hi, well im rather confused.

And im hoping you can help me.

I get all the Junior and Senior stuff, but can Senior's take Juniors lessons? I mean, I read it in a story, but i forgot what it was called. then the writer deleted the story and i was like arghhh!

but yeah, if you could like explain it all to me, I would be very grateful

xoxo

[edit]
Okay, i need to add 100 words. So, If you could explain what its called when a Senior has a lesson with a Junior, and the ages.

Oh, yeah the reason i wanted to know was because im writing a story and wanted to put that the guy has a lesson with the girl.