Reconciliation -sure: Right/wrong, asking forgiveness and making amends.
First Eucharist - probably: joining the community at the table, welcoming Christ into your body, your heart, your life. Of course my understanding of trans-substantiation has grown as I have matured ~ so perhaps that is the sacrament to receive in young adulthood with Confirmation coming earlier.
Disclaimer: I loved my Confirmation prep ~ I had wonderful teachers (a married couple) who took us phrase by phrase through the Apostles Creed and spoke with love and devotion of full membership in the Catholic Church so that at my Confirmation as I received the last of the Sacraments of Initiation and professed the creed I was so happy and proud to claim this Church as my home.
Can an eight year old take hold of that? I wonder?