Am i overthinking ?

So i went to do tadi today. We normally hold each other's phone. Her fingerprint is on mine she has access to everything and reads my chats. We're very open with each other. I rarely hold her phone though, if i hold it it's probably something she's showing or on one ocassion that i was viewing her gallery. she doesn't stop me when i hold her phone and i don't feel comfortable checking her chats you know, but since she is comfortable and i have nothing to hide from her i don't mind her checking mine. So today an interesting episode happened. I messaged her on WhatsApp that I'm at their gate when i came. She came and we sat down. She was gisting me about school, she needed help with something so i picked her phone, the first thing she told me was she doesn't have data (okay i thought but we just talked not up to 20 mins ago on WhatsApp) i didn't think much, i said let me check her data plans to see if it's same with mine, she moved closer checking what I'm pressing. I was all casual about it. I now said let me turn on the data (maybe if i put it on flight mode and turn it back on it'll work) as i was about to on the data she snatched the phone from my hand and kept it to her side. Wow this is new i said to myself. I kept quiet thinking, she now asked me what's wrong? I told her nothing. Rather than keeping quiet and overthinking, i opened up to her and asked calmly when did we start hiding phone from each other? She said she was just playing? (hmm like that?) Then i pressed but you told me you don't have data, how comes we've been chatting since morning till 20 mins ago, all of a sudden your data finished now. She said enh can't data finish? Then she said me if she asks me for my phone sometimes i don't give it to her but since it's me now I'm taking it personal (wow she has never asked for my phone and i didn't give it to her, but why is she defensive now rather than explaining ?). I kept quiet waiting for her to talk, she stood up and left. I don't want to misunderstand the situation hence why I'm bringing it here? Could it be that there's something she's hiding because this is strange.