Is she interested or is she just joking?

So, this is this person who recently joined my group chat. It's originally a chat for my old friends so I had my picture on the profile. But as new people were joining in, I decided to change it. This person starts flirting with me, calls me cute and remembers all kinds of details about me that we talked about long ago (and even I forgot about). I kind of have my guard on as I don't know them personally, so I don't reciprocate the flirtation.

Whenever I ask what her intentions are they end up saying "They are joking" or they are just trying to annoy me. So, I'm kind of confused over this and will appreciate your help.

Is she interested or is she just joking?
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