Child 10 day NE ticket & MDE/FP+. Issues when child turns 10?

[Girlie1]

I have a few 10 day no expiration tickets that I bought over the years for my youngest who will turn 10 in April. There are a few days on each. We are travelling to WDW about a week after his birthday. In the past when we went to the park and the ticket was for a child and they were over 10, the cast member told me to go to Guest Services to upgrade to an adult ticket (which they always did for free). I attached one of these sets of tickets to my MDE account for my son for this trip as I do not have any adult tickets for him. I am concerned about what may happen when we go this year considering I already arranged all of our FP+ reservations. Has anyone been in this situation? Do I even need to bother going to Guest Services to upgrade to an adult ticket anymore? Maybe they won't care or notice but I was wondering and thought I would come to the experts. .