You hit the nail on the head; these early marks are meaningless. These are barely mentally formed children. We do everything we can to avoid having them be responsible for their choices because honestly they aren't ready to make serious decisions. Except we begin the gauntlet of constant rating and judgement in school with aftereffects that carry over throughout their academic lives no matter their circumstances. Their success or failure is essentially a proxy for their parents success or failure, or a accident of circumstance more often than it's any genuine ability.

If any marking is to count or mean anything it needs to begin when they are adults capable of making real choices.