Do some reading on cannabis seed genetics. It’s like children from human parents. Having same parents does not mean the progeny will have the same genetics. I do not share same DNA with my siblings, tho I do share the same parents.
PS - just because a seed was created earlier in time does not mean it will grow bigger. For example - I have 3 year old seeds that will begin the process of life when they are germinated, same as some 2 week old seeds fresh from a plant. Time starts once germinated