Citizenship - Reckonable Residence

when will the reckonable residence start in my case,,, from the date the Dublin Airport immigration office stamp my passport "purpose: work (a very big green stamp with a lot of details)" or the date I went to get my first GNIB card? It's just a bit confusing since the only time i know I won't be counted is if I'm a student, A.S. or simply illegal, none applies to myself.

there is almost 3 months gap between these 2 stamps, so i prefer to go apply on the airport immigration stamp date. do you think it's the right one?

Thanks!
Mr. I

from the day you were officially given a stamp and card