How can I help this girl?

[424]

So there's a girl who's in my school in the year below me, and she's made a twitter account posting lots of inappropriate nudes (which have her face in so you can tell it's her). She's also putting tweets such as "I do free meet ups, if you can make it to me I'll **** you" etc even though she's only 14/15. (She pretends she's 19 on the account).
A few people in my year and her year have found out about it but she doesn't know. In school she's so quiet and shy.
Because I found out from someone who already knew, I know that in a matter of a few week everyone in her year and mine will know.
Although she shouldn't be doing it, I really feel sorry for her and want to tell her to take the account down before everyone finds out, but how can I tell her? I have her on Facebook but what can I say? I want to help her out before everyone sees

[Second]

You are a good person but if they are already posted on Internet you can't really know who would have them and who wouldn't look if you want to help have a one on one talk with her discuss the reasons behind it you can't stop people from seeing it so what you can do is actually be there for her as a friend when things get tough she is 14-15 she doesn't know any better but she needs guidance because that's no way to seek attention it's the wrong kind anyways

[Alyssa]

I would just tell pull her aside and tell her about it. I think you are doing the right thing by trying to warn her before it really gets out, but since you say a few people already are aware, I am sure it will spread fast. It would really awesome if you told her like pronto so she has a chance to get it down before too many people see! I know its likely awkward for you, but believe me I am sure she will be very very thankful. Just say "I just wanted to let you know I have heard around school about your twitter account and I wanted to give you a heads up before too many people see it"

[Nicole]

omg! you should help her! you know your a good person just tell her personally so she can realize she did something wrong.. maybe she just need help (and maybe friend)