My husband and I want to care for my student?

My husband and I are in our mid-thirties and have two biological daughters. I am a high school English teacher and I've been teaching for 10 years. Last year I taught a girl (she is 17) and since then we've been very close. In the middle of the year I had her, she gradually opened up to me and we have lots in common. I've known her for a year and a half, walked her through some tough times, and we both have a history of sexual abuse. We relate and understand each other, and I love her. I tell her that I am here for her and she has expressed appreciation and love in return.Last week, the girl was in a car accident and lost her mother and father (she's an only child) and she has been in the hospital since. She was in a coma for three days and broke her arm, and now has a concussion. She knows her parents are gone, and is attending their funeral this weekend. Her aunt may become her guardian, but my husband and I would like to. She has a few family members, but the new primary is willing to sign over rights if we decide to take guardianship. My husband and children have met her and known her for a while, and are perfectly accepting of the idea.

My goal has now become to show this girl how much I love her. She has expressed that she is comfortable with me and we are considering asking her if she'd like to live with us. She will be 18 in less than a year and if she chooses not to live with us we will always keep the invitation open.What should we do from here? How should we offer?