Stepfather/stepchild was established when child was 20 yrs old. Can K-2 follow to join?

[Jamaican JNR 2]

Hello everyone! A friend of mine needs help. I hope someone can give me an answer so I could tell her what to do. Here are the facts of her case:

1. Her fiance filed a K-1 visa for her and K-2 for her kids (I-129F). She indicated in her DS 156 form that her kids will follow to join.

2. She is now in the US, married to the US citizen petitioner. The marriage between the K-1 and the petitioner occured when the K-2 (child) is already 20 years old.

3. She has just filed for her adjustment of status recently. No approval yet.

4. Her eldest child who was indicated in the I-129F petition is already 20 years old.

5. Her 20 year old child will follow to join before she ages out.

I read somewhere that "The stepparent/stepchild relationship must be created before the child reaches the age of 18." She is not sure if her 20 year old child can still follow to join. My questiona are:

1. Can her 20 yr old child still be considered as a derivative, and therefore can follow to join, even if the stepfather/stepchild relationship was established when the child was already 20 years old?

2. If the child is still elligible to follow to join, what should be done so she could get a visa (please note that the K1 has already filed an adjustment of status but no approval yet)?

3. Who should my friend contact to proceed with the follow to join if her 20 yr old child is still elligible.

I hope someone can help her. Thanks.

Whta you read applies to K-3 and CR-1 visas, not to the K-1. If her visa was issued LESS than 12 months ago and she has her receipt for filing the adjutment of status, YES any unmarried child under age 21 can get a follow to join K-2 visa. They will need to have their own medicals, interviews, visa applications, pay the fees and pay the adjustment fee when they arrive, $1010 each. They will use the same NVC case number as for her fiancee visa. Contact the embassy to schedule appointments and get details of exact forms needed

Good advice