I was talking to my mom about joining a sports team at school, but I said I wasn’t sure I wanted to do it because I heard a girl I find annoying might be on it. I told her about some things she said and does that might indicate she does something that could be considered gravely sinful. When I was talking about her, I kept her identity private until my mom asked what her name was. I wasn’t sure what to say but I ended up saying her first name. Was this detraction?
I think you told your mom more about that girl than was necessary, so yes, it sounds like detraction.
Since it is your mom, and she is not likely to gossip about it, I think the offense is not very serious. Just take it as a learning opportunity. You see how one statement leads to another, and even the first name might make it possible for someone else to identify the person. Try not to do it again.
2477 Respect for the reputation of persons forbids every attitude and word likely to cause them unjust injury. He becomes guilty:
of rash judgment who, even tacitly, assumes as true, without sufficient foundation, the moral fault of a neighbor;
of detraction who, without objectively valid reason, discloses another’s faults and failings to persons who did not know them;
of calumny who, by remarks contrary to the truth, harms the reputation of others and gives occasion for false judgments concerning them.
You were confiding in your mom. I don’t think it was detraction. Your mom has a vested interested in the people with whom you associate…for your safety, especially if you’re a minor. So there was a valid reason for discussing this. Detraction is: the sin of revealing another person’s real faults to a third person without a valid reason, thereby lessening the reputation of that person.
I think it depends on your intent. Were you sharing this information because it was necessary for your mom to know, or because you thought it was interesting gossip?