What should I do about my ex co-worker?

So my ex-coworker randomly messaged me this morning after 4 months of no contact. I’m the type of person that doesn’t like to have personal relations with the people I work with. I’ve told her multiple times in the beginning that me and her are only acquaintances. I believe she was offended by it and made it a goal to become my friend.

I’m a strong believer in the saying “Not everyone is meant to be in your life”. I have nothing bad against her, I can’t recall a time when she did me wrong, I just don’t see her being within my close circle.

After I had left that job, I had no interest in hanging out with her and she got annoyed with me for declining her invitations to things.

The last conversation we had through text, she sent me 2 red flag emojis because I chose to hangout with some else and not her. It seemed like if I get another red flag from her, she would cut me off. So I chose to cut myself off from her, for her. Then she randomly messages me this morning.

At times I felt like I was the bad guy for not allowing her into my life but why would I be in the wrong for that? It’s my life, I should be able to choose who I want to hang with.

What are you guys thoughts on this? And please, be respectful.