So I just recently received my sons citizenship/social security cards, he is now 3 years old. Can I go back and redeem the two years I wasn't able to add him to my taxes?

[Bsch4477]

You can amend the returns to claim the child as a dependent but you cannot claim child tax credit or earned income credit retroactively. 

[NCperson]

so what is the value of amending the return? 

[Bsch4477]

Before 2018 you could get a personal exemption for dependents.