Girlfriend was taking nude selfies, but has never sent me one

Am I being paranoid? I've been seeing someone since August. In terms of looks and personality- she's the woman of my dreams. Last week, I was spending a few nights with her at her place. She said she'd take a bath and that she'd be a while. About 15 minutes later I'm looking for my phone and can't find it. I decide to check if it's on her bedside locker in her bedroom. The bathroom door was closed, so thinking that she was still in there bathing, I opened her bedroom door without knocking. She was there, standing in front of her mirror, nude in just high heels, taking a selfie(selfies?) on her phone. She looked absolutely incredible but grabbed some clothes to cover her modesty and shouted at me for not knocking.

I apologised and sure enough my phone was there, on her bedside locker. She didn't say anything else when she came back and I didn't think anything of it either. But it's been playing on my mind the last few days. I know how this sounds, but she has never sent me a nude selfie of herself. And it's a week later, so if she'd planned on sending me one of the sexy selfies she was taking when I walked in on her, surely she would have sent it by now?..

Maybe I'm being paranoid, she could have been taking them for herself... But I'm paranoid that it was for someone else, she's been a bit off the last fortnight or so.. Am I being paranoid, or overthinking things? I know it may sound a bit trivial to some but it is playing on my mind. Any thoughts?