Little sister vaping!

So my 15 year old sister has been vaping for a while now but recently she's been vaping more often. I know the majority of kids will try it and want to fit in with their friends but I think it's disgusting at that age and I'm worried about her health as well as getting addicted! She's been asking me for money so she can buy them off someone down the street! It sickens me that this is the length that kids are going to just to fit in. I obviously don't give her money. I don't want to keep this secret for her anymore and I want to tell my parents. Is this the right thing to do ??