You're trying to say that 21 is the de facto standard for the rest of the US because there are no other competing laws that challenge the validity of CO's laws.
I'm saying that logic is faulty. I'm not saying that the reason laws from CO don't apply to the rest of the US is because that's not how the government works. I'm saying that laws from CO don't apply to the rest of the US because there is zero reason they would. CO has precedent on the legal age of consumption for marijuana, and other states are likely to use that as a guide when legalizing in the future, but in the mean time you cannot apply CO's laws to other states because they're sovereign entities.
I think I have better wording for what I'm trying to say using the Law of stuff I Learned In Geometry:
If weed is legal, then the minimal age of consumption is 21.
If the minimal age of consumption is 21, then 14 is too young.
Therefore, if weed is legal, then 14 is too young.
And yes I know that weed isn't legal where he lives but the point still applies I think
Gah if this doesn't work I might just stop