Re: She is insecure.
She took all the trouble of being caught with a phone and all, so she obviously values you more than other guys. You can count on that.
Okay your responses ain't look too bad but, my advice is, if you keep patching her up like: "I want only you." you'll be feeding this insecurity. She'll just be with you to cover her insecurities. She might be super confident when she's around you, but when you're away she'll keep being that scared girl, as an individual.
So, in my opinion, you are not doing her a favor by trying to make her feel better about herself. Her approach to this whole relationship situation doesn't seem really healthy so, you gotta behave accordingly.
What I'm trying to say is, she won't try to fix her insecurities if you tell her that they are okay. No, they are not okay. You gotta be willing to walk away if she doesn't improve herself. Because bro to be honest, she doesn't deserve such a high-value man like you if she doesn't value herself in the first place.
Bottom line, try to understand her insecurities, doubts and fears but don't go soft. For you two to have a healthy relationship, she needs to fix these and she might need you more than ever to complete this process.
It's not about who I was or who I'm going to become.
It's about who I am. Do it right here, right now.