There are a couple of coaches who are starting a new team next summer and want my son, a 2018, on it. A few of the kids that they have told me that are a part of this are a year older in school than my son. When my son was younger he always played up with his brother but starting last summer he played with his year of grad. I hesitate to have him move up because he wouldn't be as physically mature as some of the 2017's he would be playing against. Could he play with them, definintely yes....would he stand out...probably not. Is there any advantage to a kid playing up in the summer or would it generally be recommended to keep them with their year of grad?
IMHO, I feel it's always a great idea to "raise the bar" and see if the player can raise his level of play. If he doesn't or can't, that's OK as then gives one a better reality check. And I don't think it can do any harm, unless the player has a really weak ego and in that case it's good to learn of that too.