I think Caitlin Blackwood has the right look, too, but I'm worried that she's too old. She definitely looks older than 12, and if we're looking at her returning for The Last Battle
, I'm afraid she'll look like an adult in that.
It's rather tricky business with the age of the actress because we may well have one or two films sandwiched between SC and LB. I'd like to see them cast someone who is 11 or 12 and young-looking at that (maybe check and make sure they don't have any basketball players for parents) so that they'll hopefully still look like a teenager even if LB isn't filmed for five or six years. I'd hate to see another Will Poulter situation play out!
I guess one potential benefit of casting someone who is older is that you already have a sense of what they'll look like as an adult, so if they're already young-looking as an older teenager, you don't have to worry about them changing a lot in between filming SC and LB. I just think SC would be a more effective film if it's through a child's eyes rather than a teenager's.EDIT:
I ran across a thirteen year old British girl named Lily-Rose Aslandogdu that might be a possibility. (Great name for someone in the Narnia franchise, isn't it?) I had never heard of her before, but she starred in a "second a day" style short film
about the Syrian refugee crisis. It imagines what it would be like if London were Syria and it's an upsetting and very emotionally charged video, but it definitely made it easy for me to imagine her playing Jill, a very vulnerable girl who had grown up in war-torn England. I think she has a good look for the character as well. If she hasn't grown too tall, I think she could definitely be a contender for the role.