Rick Riordan said this quote

If I had still been an immortal, I might have flirted with her myself. But I was now a sixteen-year-old boy. My mortal form was working its way upon my state of mind. I saw Sally Jackson as a mom—a fact that both consternated and embarrassed me. I thought about how long it had been since I had called my own mother. I should probably take her to lunch when I got back to Olympus.