Yes, and it often is. Autism can be missed in childhood for a number of reasons: the signs may be subtle, the person may be high-masking (consciously or unconsciously hiding their differences), or their difficulties may have been put down to anxiety, depression or other mental health diagnoses.

This is particularly common in women, in people who did well academically, and in people whose autistic traits did not match the stereotypes their teachers or GP were looking for. Receiving a diagnosis in adulthood can be a powerful step in making sense of your experiences.