So, a little backstory.

A friend of mine is wanting to set me up with a friend of hers. She shows me her Instagram page, and then I proceed to send a friend request. I now think this was a mistake. Anyway, I go through her pictures, and like a few that I thought were nice. I was waiting for my friend to set up an introduction or something, but at work today, she says, "hey, my friend is asking why you haven't messaged her." I was waiting for an official introduction as I'm not a fan of messaging anyway. Is there any way to come back from this? Should I DM her? What do I even say through DM to a complete stranger?