Consistent with evolutionary expectations, young children do assess the age of potential models

From The Secret of Our Success by Joseph Henrich. Page 46.

Both as an indirect measure of competence or experience, and as a measure of self-similarity, age cues may be important for cultural learning for two separate evolutionary reasons. For children, focusing on and learning from older children allows them to learn from more experienced individuals while at the same time providing a means of self-scaffolding, allowing them to bridge gradually from less to more complex skills. The idea here is that although a learner may be able to locate, and sometimes learn from, the most successful or skilled person in his community (say, the best hunter in a foraging band), many young learners will be too inexperienced or ill-equipped to take advantage of the nuances and fine points that distinguish the top hunters. Instead, by focusing on older children, young learners can isolate models who are operating at an appropriate increment of skill and complexity above their own. This creates a smoother and more continuous process of gradual skill acquisition, as learners move back and forth from observing older models to practicing, and repeat the process as they grow up. This is why, for example, younger children are often so desperate to hang around their “big cousins” or older siblings, and why mixed-age playgroups are the standard in small-scale societies.

Consistent with evolutionary expectations, young children do assess the age of potential models, perhaps by assessing physical size. Young children often prefer older models unless those individuals have proven unreliable. They trade off age against competence and in some cases will prefer younger but more competent models to older, less competent ones. For example, in one experiment second graders preferentially imitated the fruit choices of their fellow second graders over kindergarten models. However, when shown that some kindergarteners and second graders were superior “puzzle solvers, many second graders shifted to the fruit choices of these good puzzle solvers, even if they were sometimes kindergarteners. In general, children and infants shift their food preferences in response to observing older, same-sex, models enjoying certain foods. Even infants, as young as 14 months, are sensitive to age cues.