Hi Stefan,
It is unlikely that this girl likes you.
The chances that she does are slim.
Even though she has shown signs of interest by staring at you, initiating conversation and even calling you a nickname, she doesn’t appear to be serious about taking her relationship with you to a romantic level.
This is most likely why she didn’t say that she liked you back when you told her that you liked her.
She may have been showing you all these signs of interest just to gauge how you would react and whether you are attracted to her.
She knows that you are and that is probably all she really needs at this time.
Again, she’s not willing to take her relationship with you to the next level as far as romance is concerned.
There are some girls who will act as though they are interested in a guy, but the main reason why they do it is to just make sure that they have a decent number of guys around them that they know could be a possible romantic option at some point in the future if they chose to pursue it.
You could be one of those guys to her.
This doesn’t mean that you should hold out hope that at some point in time she will want to become romantic with you.
Oftentimes, a girl like this would just want to know that there are romantic options around her, but the likelihood of her taking advantage of those options are slim.
She would rather date someone who is outside her immediate circle of friends and close acquaintances.