Transitioning from Early Intervention

My daughter is about to turn 3 and has been receiving speech, and special education therapy without a true diagnosis. As she is approaching "aging out" and I am being told scores are normal, despite that undeniable sense of something else that is hard to explain. Her current speech therapist has tried to explain a clinical impression of my daughter to help her continue but as the transition to school district evaluations is approaching I am unsure what steps to take to advocate for my child.

Is there any resource for the transitional period. She has had the "language delay" "processing delay" and "sensory issues" mentioned by those who have worked with her. I was starting to research possible Occupational therapy options and until I came to this website I was not sure of a possible explanation. Her older sister who had also received therapy from early intervention but was discharged, has continued to have very similar issues and has now in kindergarten begun to demonstrate more anxiety and behavior related behaviors that I realize have stemmed from this possible root. Family history of ADHD and sensory disorders are undiagnosed in her father and uncle as well. I am concerned that without a test or true diagnosis both my children will continue to suffer after they age out of early intervention. Please help me get them the help they need!