Even if Ichikawa gets tall remember the same will likely happen to Yamada too.xD
To be fair, Yamada, as a girl, already had hit her growth spurt 3 years prior. Hence the age progression image from a recent extra (to this chapter) that had her shoot up between grade 4 and grade 5. She's potentially still growing taller, and out, as well, but the bulk of her physical height change is possibly over at this point.
Girls just tend to mature earlier. I figured it was common knowledge it hits them earlier than boys.