Little sister has sex?

[Anonymous]

I am 19 years old and i want to ask you an important question about my sister.
My sister is 11 years old, in 4 months she will be 12.
When i came home yesterday my parents werent at home, i went straight to my room and i passed by my sisters room. I heard strange sounds and moaning, at first i thought she masturbated but then i heard the voice of a guy.
I knocked the door, waited for a response but nothing came (maybe they didn't hear me) and so i went in. The door was blocked by objects from the other side that made sounds, but the door was easy to open.
There i saw sth that makes me feel grossed out. My young sister from a age of 11 had sex with a 17 year old guy.

I was truly shocked. I talked with her about it after the guy run away half naked.
I asked who he was and all she said "a guy i met today, dont know his name".
I really wanted to slap her.
I talked a little longer about it with her. She said that it didn't really matter because its just sex. I asked her if she did it with other guys too. She had sex with 8 guys! All were ons she didn't know beside her first one, this was the biger brother of a friend of her, he is 16 and i know him very well, i thought he was a good guy.

I couldnt believe it and thought she was joking. Then she told me that its normal and that everyone of her class does it and she doesn't want to be left out.

I left it at it and went to my boyfriend to tell him all of this. My boyfriend and i are together since 3 years and had sex 4 months ago, we are both each others first, maybe that is why we are shocked.
He told me that it would be best to tell my parents so that they can talk with my sister. He said there isn't anything wrong with living that way but she is too young for it and its too dangerous to have ons and she should understand that its not legal and that the guys are practically abusing her sexually. I agree with him. I will tell my parents.

What else can i do?
Is this truly normal nowadays?

[Anonymous]

It's not just immoral, but also illegal in most places. Her partners could go to jail for exploiting a minor.

[Anonymous]

Tbh i'm afraid it is so normal for 12y/o to have sex these days but i don't think she'll change ways when you tell your parents