God never gave people authority to institute another memorial which would countermand the Sabbath memorial that He gave at creation. The disciples were not holding a meeting to honor the resurrection. They did not even believe in the resurrection at this time. Instead, they were hiding behind locked doors for fear that what happened to Jesus would also happen to them. They were afraid for their lives.
Nothing here indicates a change in the day or worship.
He was instructing the Corinthian Christians to prepare by laying aside at home a certain amount of money each week for this special gift. This was an individual laying aside, and not collective laying aside at a church meeting. There is nothing in this text to indicate there was a collection occurring in the church on the first day of the week. They were simply putting aside money that would be given to Paul later when he arrived. This way they would have more to give and avoid last minute scrambling.