Read more carefully LG. You can play competetive A internationals for one association only (but this does not include friendlies).
However, if you played for an age-grade international team in an official game prior to the age of 21, you can change to another association and represent them provided you do it before the age of 21, had not represented the original association in a competetive A international, and were eligible to play for the association you're changing to at the time you made age-grade international appearence for the original association.
Read more carefully LG. You can play competetive A internationals for one association only (but this does not include friendlies).
However, if you played for an age-grade international team in an official game prior to the age of 21, you can change to another association and represent them provided you do it before the age of 21, had not represented the original association in a competetive A international, and were eligible to play for the association you're changing to at the time you made age-grade international appearence for the original association.