As for colour of the kernels ... this can vary from one variety to another and some are much paler than others. A far more reliable way of testing readiness to eat is to stick your thumbnail into a kernel ... if the resulting juice is milky then it's ripe ... if it's clear fold the leaves back around the cob and leave for a few days.
Have grown corn for the first time this year. I found that half the kernels were informed too. I did notice that the male top flower had dropped pollen too early for the females lower down to be pollinated. I think this is the problem. Next year I will stagger the planting and hope to improve pollination. Hope this helps.😁