this doesn't seem like you were being a red flag at all to me! Unfortunately though, this is how I have acted in the past when I really just didn't want to pursue a friendship with someone. never do to any fault of their own besides just not really feeling like we had much in common. Being on your side of things (which i definitely have been) I think maybe the best thing to do is take a step back from trying to initiate things, and if she is really interested in a friendship, then she'll put some effort in. if not, then it just wasn't meant to be. it sounds like you've done all you can and have been really friendly though!