Should I file amended return if I didn't receive the CTC for my daughter? I opted out and got the lump sum for my son but I don't understand why she wouldn't qualify

my son will be 5 in April, daughter just turned 2 in February and I should have received the advanced ctc payments for both of them. I opted out of the payments before I could add a dependent, but I'm very confused as to why it didn't pick it up... she has a valid social security number, birth certificate, etc. Thank you in advance