My son has ADHD and likely autism
He's 7.5 now
He had regular seizures as a toddler
He didn't sleep for more than an hour at a time
He would never sit down unless on a very rare occasion something completely captivated him like a trainset or Lego.
He walked early, he talked early, he could multiply and knew his times tables at 3, he just started using numbers by himself, he never stopped talking and never stopped moving.
Note also though the complete sleeplessness, seizures, inability to sit still at all! Not just for circle time, I have videos of him rolling on the floor playing his switch, he doesn't even sit still if concentrating on an activity and at 2.5 he'd run into the road etc. he could follow 2 step instructions if the notion suited him. He had his own agenda.
Your child MAY have very minor additional needs, she probably doesn't from your description of a child who sleeps well, eats well, can concentrate for 6/8 minutes (my son was either no interest in concentrating or concentrating hard to the point of obsession for an hour on Lego at that age)
Early assessment is helping you and her how exactly? We've eat h fully waited, his school gave been supportive of him, we've documented everything and he's still an unfolding story.