Should I give this girl $10?

So basically I was in a group chat and I posted randomly and some girl asked who I was and I said "I'm your secret admirer" as a joke and she said "prove it and send me a sephora gift card". Should I actually carry on with the joke or would I be the joke to just give her the gift card?

Update: So I didn't send anything but since I had acquired her email address I did take the time to write a complimentary email just to break the ice or tension or whatever and come clean about what was happening.