Little sister...

If she is you slap her across the face and tell her she was stupid and needs to keep her legs closed, haha sorry if that seems harsh but I come from a family that shows tough love, ohhh and you don't do or say anything, it's her problem if my younger brother got a girl pregnant I wouldn't do anything or say anything to him, yeah he's my little bro but it's his life to screw up, not mine.

Ask her if she really is... even though you know by now... if she says yes then go for the abortion. What's up with young girls getting piped so early nowadays?

Ask her if she is or not, if yes, take her to a doctor and tell your parents too!

Be calm when you talk to her and try to be understanding. Ask her. Make sure it is in a private area where nobody is going to hear her. Also make sure both of you have a little time on your hands because she might start crying and really need to talk to you.
Good luck
xoxo

Take her somewhere private and ask.

Take a walk or go somewhere private. Talk to her about it. Tell her you are concerned and want to help. There is very strong bond between siblings. Between the both of you, you can find some way to tell your parents. There are also pregnancy centers, or hotlines to call too. A lot of pregnancy centers they give free testing. Good luck!!

First, find out if it's true by asking her. Then be supportive and help her look at options and make a decision. You can also help her break it to your parents, you know?