Mom gets autism diagnosis at 40 and her autistic son's response is heartbreaking: 'Then you understand...'

Living with autism means moving through the world while managing sensory overload, emotional disregulation, and social expectations that can feel out of step. For parents of autistic children, supporting those challenges becomes part of daily life through structure, therapy, school meetings, and careful listening. That was the case for Kate Cortelyou, a special education advocate based in Tennessee, who had been supporting her autistic son for years. But recently, at age 40, she received a diagnosis of her own. In a video posted on Instagram @onethumbgarden, she shared the news with her son, and his reaction showed exactly what that moment meant, not just for her, but for both of them.

"I did some long interviews with the doctor. And I talked to them today," Kate said to her son. "Mm," he replied, listening intently. "I am autistic." He looked up in surprise, asking, "Actually?" She nodded, adding, "So we are both autistic." As soon as her son heard it, he leaned in and gave her a long hug. It was the moment her son "realizes he is not alone." He said, "Then you understand. Then you understand why I complain a ton." "It is because of you that a lot of things started to make sense about the way that I was," Kate responded.

She later explained how the moment came together. "A few weeks ago, at age 40, I was diagnosed as autistic. When our son was diagnosed as autistic at three, I dove headfirst into learning everything I could about autism, special education, disability rights, and advocacy. I even became a special education advocate and have been serving families across middle Tennessee since 2018. I did it all for him. It turns out this entire time I was learning about myself, too." Just like Kate, many adults receive autism diagnoses later in life, many of whom go through life feeling isolated or misunderstood, often receiving treatment for anxiety or depression without knowing the underlying cause, as per a study published in Health Psychology and Behavioral Medicine. The diagnosis helped them reframe their identity and recognize lifelong traits they had never been able to explain.

The video had a deep impact on the viewers, many of whom saw their own experiences reflected in the exchange. @peachpines.wellness wrote, "This is exactly why late diagnosis matters. To show our children that they're not alone, they're part of us, they're seen." @angeliasantos17 said, "The most incredible feeling is being understood. He no longer feels alone in what he's going through. This is so sweet to see." @monto3_ commented, "I have loved seeing videos like this. This is so monumental that this can actually happen for all of us. An age where autistic people aren't ever the only one like them."

@rainydazeee_ quipped, "The first thing he said was, 'Then you understand.' Oh sweet boy, he just wants to feel seen & heard." @chef_bruns wrote, "The sense of relief and excitement from that boy is amazing. And then the moment of 'so you understand me even more now!' That's awesome. Thank you for sharing." @mountainmama.98 said, "I hope my girl is able to understand a conversation like this one day. I want her to know she isn't alone."

You can follow Kate Cortelyou (@onethumbgarden) on Instagram to learn more about their journey.