Trying to make contact with someone who pushed me away.

So I liked this girl for a while now, however we fell out of contact a year ago. She found me annoying, but I recently contacted her to wish her happy birthday, and she replied back. However I don't know how to interpret that, and I don't have any friends close to her anymore. Do I risk texting her again and asking how she is, try to find a mutual friend to talk to her or gather information, or get a stranger who she doesn't know to talk to her on my behalf. All my sources that were close to her want nothing to do with her, but if I try hard I might find someone. I don't know what to do.