Demelza's a little girl at the start

Demelza is supposed to be 17 in the TV series.

Fail? Please. Obviously, they're not doing her age exactly like the books, which would have meant using more than one actor to play the role. That would have been a definite fail as it's always kind of difficult to find a child who really looks like the adult they're supposed to become later. Eleanor is about ten years younger than Aiden, so that means she's about right for the part. And I think she's terrific.

Yea I agree, she is great and they did an awesome job, I'm calling troll on the op

She's supposed to be 13 when he meets her, the time goes fast in the books and the show. When they finally get together as a couple, she's 17. To be honest I think she looks fine for that age.