Personally, I never asked.
I guess I figured that if DD had "IT", then she'd be invited.
I held the same philosophy when it came to her moving from rec to pre-team, etc.
I remember when my DD tried out for preteam. She and seven other girls were placed on pre-preteam. The mother of the other girl my DD's age was appalled. She complained every practice about how much more advanced her DD was than the little ones (age range of the group was 4-5, and our DD's were quite close to 6). She argued until her DD was moved to the preteam group (gym doesn't compete level 2, so that group is level 3 prep).
It sucked for my DD, but I refused to beg to move her. I figured she was where she was for a reason - she needed to earn a move-up on her own. Thankfully another girl her age was added a few months later. It was slow going and mostly focused on strength - my DD "lost" many of her "skills" she'd learned in rec. The skills were slowly rebuilt.
Fast forward eight months later, her then DD quit - she was behind the other girls and frustrated. Five years later my DD is still with it, and is training level 7.
They have a group that trains TOPs. DD is out of age now, but there are still several older girls in the group who don't compete. Do I sort of wish she was in the group? Yes. But more because one girl in her training group is doing it, and another girls' mom just asked for her girl to join. So 2/8 girls are in the TOPs group. I told my Dd that if she wants to add it, she has to ask. She hasn't. I still won't, despite a small amount of worry that DD will fall behind those two girls.