Your idea is good, i think one element you need to focus on is thinking how you intend to build up that feeling of paranoia, your use of camerawork and sound will factor into this discussion.
I also think you should avoid filming at night as it can be very problematic. Look at the previous student thriller Les Tombres for an idea of some of the challenges of night shooting.
Do also develop your idea to perhaps include something else as well as following the girl, otherwise you risk your viewer getting a bit bored.
Good work so far.