What should I do about this girl?

I met this girl in high school 5 years ago. We were pretty friendly with each other, for example I would post the"tbh" posts on Facebook and she would like every last one. We were also friendly in college. We both went to the local school, but we wouldn't see each other often. Of the times we did, she seemed happy to be around me. We ended up talking at the library once for a few hours before I had to leave. It got real deep, we talked about family and a bunch of other stuff. Or if we had a class we would sit together and do homework and stuff like that. Between then and now, she got a boyfriend. Once we hung out before class doing homework and he showed up, he barely even looked at me or even said hi, it seemed like he was jealous. Here's why I ask this question: She texted me last month out of nowhere, saying she found her old phone with my number in it. We texted for a while but she ended up dropping the conversation. I left it alone but she texted me a few days ago, and the same thing happened. The first time makes sense but why text me twice, especially if she's just going to drop the conversation. Should I make an effort to stay friends and text first? I could take it or leave it, I haven't seen her in forever. I doubt our friendship would change if I didn't do anything.