Anyway my 2 cents is that it is a very consistent handwriting style - eg each y looks very similar, each a, even the angle of the dot over each i, and the m's are consistent but not usual cursive style. So my guess is that it is a well-practised personal style of handwriting rather than a 'learner' handwriting - compare it to George's note where the different instances of each letter are less consistent. The crosses at the end of Charlotte's note look more like learner writing. So I think it was probably a joint effort with a helpful grown up. Not that that means anything negative about Charlotte or the grown-up, and of course I could be wrong! But on balance of probability, not a young child's writing I reckon.
I agree with this rather forensic analysis. When you look at George’s writing, it is also very neat but much more what you would expect of a Y3 with neat writing. With Charlotte’s piece, it’s not so much the neatness but the fluency which makes it look like the writing of someone who has written a lot. And the letter m’s are very distinctive, very regular and not cursive. Would a school insistent on cursive not have corrected this?
Several posters have shown very impressive pictures of their young DCs neat writing but they still all look like young children’s writing - they have a certain deliberation about them. Charlotte’s piece looks like it has been written quickly with no deliberation.