Hello and welcome to the forum. There are many here that have wisdom far beyond mine. I am certain that others will help you too.
On the question of whether a child of 8-10 could understand what they are doing, depends more heavily on the maturity of the child’s spirit than age. Many people use the age of 12 as a guide since Jesus was 12 when he stayed behind in Jerusalem following the Passover. Luke 2: 46; 49 “And it came to pass, that after three days they found him in the temple, sitting in the midst of the doctors, both hearing them, and asking questions.” “And he said unto them, How is it that ye sought me? wist ye not that I must be about my Father’s business?”
You know the circumstance surrounding your first time of being saved and baptized. Many people of all ages feel that they are required to conform in a church. Peer pressure or adult pressures are known to cause people to go forward. As I said in my prior post, at the age of 13 I went forward to make my public confession and was baptized immediately afterwards. The pricking of my heart by the Holy Spirit had started a few weeks prior. I made the decision to wait a week in hopes my older brother would attend the following Sunday. That was a mighty long week. Every day my mind was on giving my life to Jesus and scared that I would die before I could.
The preacher may be thinking about Jesus’s parable recorded in Luke 8, the Sower. Please read the chapter and as you do, consider what soil your heart was in at that time.
If you were not fully mature at your first confession, then this second time was, pure conjecture since I am not privy to God’s decisions, the Holy Spirit calling you to himself. At the end of Peter’s sermon on Pentecost, those hearing it were “pricked in their hearts”, and you said, “gripped me”. It is the conviction one feels when they understand their wrongdoings are counter God’s grace and seek repentance. How did you feel afterwards? Had you given yourself to Jesus?
If at the second time you truly gave yourself to Christ Jesus, then your salvation is locked in - sealed by the Holy Spirit. Ephesians 1:13 “In whom ye also trusted, after that ye heard the word of truth, the gospel of your salvation: in whom also after that ye believed, ye were sealed with that holy Spirit of promise.”
Now we are not to grieve the Holy Spirit. As the bible reads in Ephesians 4 :17-32, we are to walk with the new mind, spirit, and strength given us.
John 5:24 “Verily, verily, I say unto you, He that heareth my word, and believeth on him that sent me, hath everlasting life, and shall not come into condemnation, but is passed from death unto life.”
Have confidence of your salvation!
On going forward to confess sins, let me say how I see it, please. IF your sin was publicly known and brought reproach on the body of Jesus’s church, then, yes, you would pray to God first, privately, then ask to be forgiven by the congregation. Their behavior following your confession should be one of forgiveness and love.
IF your sin was anything else, your contrite heart, heavy with the burden of the sin is to pray privately for the forgiveness of it. Once confessed, know that God has permanently removed it from His mind…as though it never happened. Your target is to love God. Love God and His only begotten Son and everything else will fall into place. Second to this is to love each other as Christ loves the church.
I am bothered that this last preacher would ask you to re-give yourself to Jesus. Every one of us still in our corruptible bodies sin - every day. We strive to be Christ like but fall short…missing the bullseye…that is what sin means…missed the bullseye. To be pressed to “give your life to Jesus” every time you sin is to make a mockery out of Jesus’s sacrificed purchase. The notion that Jesus’s blood did not fully wash away your sins because you sinned again is outrageous. Only God knows your heart. You know what you know.
My advice is to read God’s word for yourself. Immerse yourself in His Truth. Compare what I and everyone else says against the word. If we match the word - good, if not - remove yourself from these. Be baptized again? Not necessary in my opinion.
If this church requires your attendance, requires specific donations, or anything else in order to remain “saved”, run!
Blessings