If you were best of friends and you use to hang all the time, all of a sudden it's different. Think about the situation first... I don't think she likes you becuase if we did we would call esp. depending on what age you are, women are not girls anymore... we mature too. Also She probably doesn't call or text first becuase we as women are always doing something. We usually wait for you to call so we know your available for the day.
Also, she may feel the same about you, you both haven't seen each other so think of it like.. whatever you may think she probably is thinking too. Only way to find out is ask her.
The first text is usually a no. I leave that to the guy as I am worried about bothering him. However, if there has been a conversation going back and forth for a while, then I have no issue texting him back if I haven't heard from him in a while. I can't really say what other girls do though.
I always want the guy to text/call me first, that way I know that he wants to talk to me. When I text/call first I'm not sure if he wants to talk to me or if he's just humoring me. Usually though I try to text the guy first just to show interest but after a while I wait to see if he'll text me first.
Perhaps she is interested in you. I say this because in the past, it was a mutual effort. Now she may be afraid to come across as too eager. She is probably overanalyzing the situation. Girls tend to overanalyze things, then realize that they are doing so. Then they begin to underanalyze to compensate the overanalyzation . It's a vicious cycle. Ultimately, if she is into you then she is clearly just wanting you to make the first move and hoping for a relationship to come of it.
If in fact she isn't interested and you two are just really good friends, then you should call her out on it. She may not realize it. A friendship should be reciprocated.