Help: She won't leave me alone

I am 20 years old and waiting to join college. There is this girl in Form One who is making me very uncomfortable. She says she is in love with me, loves everything I do and wants a relationship with me.

I have clearly told her that I am not interested, but she is crazy. She got my number and just won’t stop bothering me. I have warned her severally, including sending my friends to her, but to no avail. She tells them it doesn’t matter if I have another girl or not as she is in love with me and that I should not dare to break her heart. I am stuck and need advice on how to get rid of her.