Hi Lute,
I'm not a parent, so I can't give you that perspective, however, I can share with you my feelings and thoughts. I will be honest, I'm a CSA survivor, so maybe I'm bias, but I am just going to be honest with you.
Any and all sexually activity under the legal age is abuse. They claim that children/teens don't know enough to understand what they are actually doing, while an adult is supposed to. I beat myself up for certain parts of the abuse I went through because I knew it was wrong and I didn't do anything. My story is different because what happened to me was not consentual. In your case, I think, the way people probably look at it is that with the kids your age it was an experiment for you guys. You guys were just trying to figure things out. They probably didn't make it into a big deal because you were teens and teens experiment. With the teacher, I think it was made into a big deal not only because it is illegal and he could be fired and put in jail regardless if you agreed to what was happening or not, but it was also a big deal because in society's eyes, the teacher was/is old enough to understand what he was doing and you were just a teen so you didn't understand (even though it sounds like you did). It is confusing, I know.
Hugs!

Be well,

Celtic