If the church allows the kids to help in the way in the original post, I hope they have been properly trained and understand the serious nature of what they are doing.
At my parents’ church, it used to be only adults serving as ministers. Seldom, teens were encouraged to participate.
I do see some teens assisting the cantor/organist/pianist as an example.
Some kids do stand with parents acting as greeters/ushers, helping to take up the collection, handing out bulletins, and/or opening doors. The parent(s) are supervising them as well.
I did not have a long training class to distribute Holy Communion at Mass. My mother was a minister and “trained” me. I was allowed to do that ministry after I got confirmed as a 17 year old many years ago as that was the requirement then for most things you had to be confirmed. Keep in mind, I looked much younger than 17 if I did not fix up my hair, wear some makeup, and dress up a lot.