Needing Advice .. Anyone? heh

Sooo. Y'all I have some amazing news! 
I don't know if I should feel excited or nervous. 
Being in ColorGuard you meet a girls (and sometimes a couple of guys). Well, me being the open and caring person I am, I'm friends with everyone! 
I told all my guts friends guy or girl. That if they ever needed help or a place to stay that my front doors were always opened for them. 
Well one of the guard members, a girl, which is a close best friend of mine, was having tons of trouble at home. Not stating a name or details of the situation. But let's say it's bad. She's been bumming off of her boyfriend and a couple of other friends just to have a place to sleep at Bc it's so bad at home. Now I never actually knew this. I knew she stayed at her boyfriends a few times but I didn't know all of this. 
Wel recently she got a call from the school from her friends parents saying that their kicking her out and she isn't allowed back to live with them anymore. They started to accuse her for some very bad things that she swore on the Bible she never did. And I trust her. 
Well she finally came to me. Her boyfriend asked to talk to me for a min during my class at the end of the day a few days ago. 
When I got into the hallway she was standing there looking like she'd seen a ghost. As soon as I asked what's going on she broke down in tears. She fell apart and held onto me freaking out on what to do. 
So I called my dad up and explained him everything and he agreed to let her stay a few nights. So she comes over and my dad started to ask questions and she explained everything. 
It's amazing what a smile and happy attitude can hide. I never knew how fallen apart and broken my best friend was until she fell apart in my arms begging for help. And then breaking down again just explaining her situation. It literally killed me. 
I never knew how little stuff she had. She didn't have underwear. She didn't have deodorant, tampons, hairbrush, tooth brush, a fitting bra. She didn't have anything. Literally. She wasn't even wearing her own cloths. They was her friends cloths. She literally fooled everyone. Everyone believed she was this happy 16 year old girl who had everything. 
We a excat total of $942.62
5 outfits 
2 pairs of shoes
Panties
Deodorant 
Tooth brush
Tampons
Everything!!
My dad and Mom, over the passed few days, have been talking about something. 
And yesterday they finally brought it out to discussion. 
They want to foster her. 
At first I was excited. I was like heck ya!! Hehe. I was prepared to treat her like my own sister, well I kind of already was. I mean anyone would be excited to live with their best friend. Am I right?
Well now. I'm started to get really nervous. My dad tells me not to worry about it Bc he is getting it done weither who says what or whatever. But I can't help but feel nervous about it. 
I mean what if her mother doesn't allow it and she is forced to go back in that hell hole?
What if her last "guardian" gets her mother to sign temporary custody papers?
I asked dad those plus more and he told me. Not to worry about it. That she is gonna stay here. 
But I'm still worrying. 
Should I be excited or nervous??