There were about 120 in the upper on Pentecost. At that time they chose Matthias to fill Judas’ spot. Matthias had been a disciple from the beginning of Lord’s ministry, just not one of the twelve. Remember when the Lord send out 70 disciples, giving them miraculous power? Matthias may have been one of those. Anyway, the apostles had plenty of help to baptize 3000 souls. I guarantee that they didn’t sprinkle either.
I agree....they dunked them! You know what that means...they’re Baptists! The only denomination mentioned in the NT! :)...just like John the Baptist!