It reminds me of Elena and Cristina, around Cristina's communion. At the time both girls were the same height and Cristina eventually surpassed her eldest sister height.
The same will apply to Leonor and Sofia, it seems Sofia has more Borbon genes than her sister, she will be taller for sure. Leonor however is more lady-like like Letizia, she got from her mother the petite and delicate posture and physique. Both girls are so diferent but so precious.
Leonor's hair is getting darker but it suits her more that way, it will make her blue eyes stand out even more.