How would you react to a sexualizing dm from a female?

A girl who appears to be in her early 20’s sent me a dm that said: “Hope this is not too weird to say but your milf face makes me horny lol”.

And I thought wth? First because I’ve never received attention from a female and second because she’s related to a friend of mine and I found out after doing some stalking on her page and thought it as strange that she didn’t care about putting herself on blast when I could easily tell my friend she said that. And I also thought wtf why me?

Now I don’t know what to say or do because it shocked me. I’ve never been with a girl before and wouldn’t be opposed to trying it. But the way she come on to me tells me shes not looking for anything serious. I could be wrong tho. If I were to respond what should I say?