Hi Ice, sorry to hear this.
No matter how this turns out, Teenage Stupidity thinking such things are funny to talk about or she is/was serious, both you and your girlfriend will never be able to trust her as you once did. You will always have this in the back of your minds.
So "you" will have to decide how to deal with it within yourself as well. Your GF will be hit harder by this than you so keep that in mind also.
I have no answers for you. I can only try to forewarn you of things you may need to think about that may not have crossed your mind while in the moment of crisis tonight.
Unfortunately the die has now been cast for a long lasting mental/emotional wound that will need attention for some time to come. I wish you well and think that you are doing the best that you can at your present level of awareness.
I commend you for taking action. You cannot
Mollycoddle her in this situation. It was her who initiated this by using either poor judgement or having a problem she doesn't understand how to deal with properly.
Since you are an adult filling the role of a parent/guardian of your GF's daughter's welfare & the rest of the family, you are doing the natural thing here.
No child under legal age has any such thing as a "RIGHT" to total privacy. They are still LEARNING how to interact with the world around them as their Biology changes and their minds are learning how to function. As parents it is our duty to instruct and guide them to the best of our ability so that they can have a full life. Whatever that might turn out to be.
We must also PROTECT them and ourselves. If you were teaching her to shoot a gun and she pointed it at you or looked down the barrel or pointed it at her foot while it was loaded you would stop her and then explain WHY those actions are DANGEROUS and unacceptable right?
As with anything (Thoughts or Actions) that could harm her or others, you would want/need to intervene to protect and teach her a WISER WAY of doing or thinking.
I got to deal with both my own children (2 daughters) and older step children (Son & Daughter older than my own.) through various marriages.
My experience may give you something to think on, I dunno?
I was in my step daughter's life from the time she was 12 until she was 19 years old and went into the Army to piss off her Biological Father.
As she was growing up she had told me on many occasions that she hated how her Mother seemed to pay me so much attention and that she was jealous of it.
Her mother let her get away with WAY to many things in "my" eyes. She wanted to be her daughter's FRIEND, not her Mother. Well, I had already been a father of two girls for sometime before Her and her children had come into my life. So, I was just going to be their Step-Dad. Not their friend.
Their Mother use to get upset when I wouldn't let them have their way. And even more upset if I were to discipline them. ( I never hit, spanked, or did anything physically harsher than restrain them from trying to hit someone.)
A few years after their Mother and I were divorced & they were adults now, the daughter was pregnant and got an abortion but didn't tell the family. She called me that night after she had it done and was beside herself. I talked her through her feelings over the phone and felt her PAIN as best as I could.
A week later I get a call from her Mother (My now Ex.) who proceeds to BITCH ME OUT!!! She was pissed that her daughter called me first before anyone else. The daughter told her that she called me and that I had helped her get through that first night. She was also pissed that I didn't call her right away to inform her of her daughter's distress. (Like I was going to betray the girl's trust. NOT!!)
Fast forward two years and she's pregnant again. By some guy that wanted her to get another abortion. (She never did tell me who he was.) But she decides to have this one on her own instead.
I get a call at 1 a.m. and it's my Ex asking me to come to the hospital. Her daughter is in labor and is asking for me. I comply and when I get there the daughter has the Nurse remove her mother (Who did NOT want to leave.) from the delivery room.
After the birth of her son, her Mother got me to the side and finally asked, "Why is it that she ALWAYS reaches out to YOU when she is in need? I have done everything for her and "I" was with her at every one of her Lamaze Classes so I could be with her at the birth of my grandchild, but she put me out and brought you in. You two ALWAYS fought like cats & dogs while she was growing up and she'd come to me in tears telling me how unfair and mean you are. I don't understand."
I told her that children NEED their parent to be a PARENT and not just another friend in their life. I told her that I too had asked the daughter why she called me that night and not her Mother.
This is what she told me, "My Mom or my Dad would just say whatever they thought would make me feel good, even if it wasn't the truth or what "they" really thought. You have NEVER lied to me and always told me what you thought even if it upset me. I always knew, even when we fought, that even though you aren't my REAL Dad that you do Love me as if I were one of your REAL daughters. You never treated me any different than you did your own daughters."
Later that day I was alone with the daughter in the recovery room and I told her how upset her Mother was. She said to me, "Had it not been for you 2 years ago, I would most likely have killed myself that night. Also, due to you being truthful with me I was OK with getting pregnant again. To be honest though, I was just REALLY scared and wanted YOU here because I KNOW that YOU would not let anything happen to me!! Thank you, I now have a beautiful baby boy to Love & raise."
I hadn't seen her in person since just before she went into the Army. Almost 7 years had passed between then and the birth of her son.
At no time while raising her would I or anyone else have ever thought that she would've reached out to me of all the people available to her in her times of need.
I'm just very very glad that I was available to her at those pivotal moments in her life.
She taught me that you can never really know to what extent your interactions with children will affect them.
The point of my long winded stroll down memory lane here is,........... for YOU to just be YOU and keep doing what you FEEL/THINK is in the best interest of you & your family. Add to that making damn certain they KNOW & FEEL that THEY are the most important priorities in your life and that you Love them no matter what.
Ok, enough of an Old Man's ramblings.
Carry on everyone.
lulz