If Zendaya was a bit younger and had a different hairstyle, I could totally see her as Clementine. She's African American but lighter skinned, she has a very similar eye shape to Clem as well. However she's 17 and definitely looks 17.
Same with Madison Pettis... Although she's 15 closer but I don't think she has the look. She's too... Polished and older teenish.