Don't rush it. Casually ask her out, in a way that makes it seem like its not a date, when it really is. Make it special too. Her reaction and interactions with you will let you know if a relationship with her would work. Don't be clingy and don't rush into things, it'll make you seem desperate and will push her away. Its part of how I keep my gf around, I keep my clingyness and my other desperate tendencies at bay and try to come off as confident, its worked thus far. Good luck