Am I in the wrong in this situation?

Since my mom passed in 2008, things havent been so great with my family. Ive managed to contact and keep in touch with most of them and pulling the fam back together. I thought it was going great until recently. Ive been trying to hang out with my 17 year old niece for months now since i havent seen her in so long. She promised me she would come tonight and spend the night. Now, checking my facebook i see she went to ashland which means she just went to her friends house or something. She tried using me as an excuse to go out on friday because she was grounded. Am I wrong for being pissed and basically saying screw her anymore?