I suffer with anxiety about a relationship

So basically I've been talking to this girl for a while and actually she was interested in me and had a crush on me for weeks now and we actually been getting closer everyday like in our calls and when we see each other and she's definitely not a texting person so ik she's a dry texter but in school their are some days especially in the morning where she doesn't want to talk to me like she's just quiet when we walk together around the school before class and some other days especially after school she shows a lot of interest in me so idk if I'm just overthinking everything she does or not and I have actually figured out I have been on my phone around her like when she's talking to her friends idk if I should be on my phone and let them talk or just stand their listening to them so I'm trying less to not be on my phone especially when we talk