I don't think you did anything wrong. I hate people striking up a conversation like that as well.
You can train yourself not to panic, deep breaths, focusing on something in the middle distance, closing your eyes, counting to ten - whatever works for you. And then you can ride a situation like this out. Either by masking your discomfort or giving very curt replies. You can also just say "I'm very sorry, I'm not in the mood for a chat." But you mustn't worry that you made an extrovert sad. She'll get over it and maybe learn from this experience as well.
I see from my own behavior that more and more stuff is done on my cell phone and less stuff on a PC. I think eventually everything will be merged into a single device. But I wouldn't bet on the form factor yet. Whether it will be AR/VR headsets or a form of tablet or a tech yet to amaze us - IDK.