Just being a teenager??

My niece (husbands brothers daughter) is visiting her dads side of the family (dad, grandparents, my husband and I). She's here for winter break. It's sad to see her so uninterested in everything. Her dad, husband and I took her to the mall and gave her 100 to buy anything. And getting her to buy anything was like pulling teeth. She just wanted to go home and watch Netflix. Yesterday her grandma, (my mil) baked cookies but she didn't want to participate. It was something she agreed would be fun ahead of time so it's not like we forced her.

We don't know if she's depressed, hormonal, just being a teenager or if something is going on at home with her mom and step family.

I'm going to have her over for a sleepover soon for one on one girl aunty-niece time. What phrases can I use to encourage her to open up? In the past she's confided in me most because I'm easier to talk to the. Her dad or grandma and closer to her generation and female duh lol.

Anon because I don't want to risk anyone from her step family reading this.

Oh, is like to add: she doesn't actually have a phone that has good internet. Certainly not 4g. So she really doesn't have her head buried in her electronics devices.