[Q] Does I-526 have to be submitted before a child turns 21 years of age?
[Q] I heard it's important to submit I-526 immigrant petition before one's child turns 21 years of age. Why is that?
That is true only where the subject child wishes to immigrate as a dependent child of the principal alien investor. However, if the child wishes to apply as the principal alien investor, then it does not matter whether the child exceeds 21 years of age.
To clarify, it's important that the I-526 petition be received at an appropriate USCIS office before the dependent child wishing to immigrate together turns 21 years old.