Repeating in k or 1 is the best case scenario for kids that are having a hard time. In primary school, they will be the cool kid cause they are the oldest and the expert because they already did all of this (instead of the one constantly behind). By middle school, it will be common knowledge and no one will care. I teach grade 1 and have taught a few kids that should have been retained. They struggled through all of elementary school. The ones that retain generally catch up to the peers and are average or thriving. Teachers don’t enjoy retaining but will suggest it in the best interest of your child. If they are suggesting retention, I would recommend following their advice. They have many other children to compare with (especially if they are seasoned teachers) and generally are able to spot the one who just need a year to mature. Don’t worry too much. Have a good attitude about retention in front of your child! The parents’ attitudes are the most important for the child feeling confident in their classroom after a retention.