Quite a large number of adults have difficulties in life without being diagnosed with a learning disability (or learning difficulty) on time. This might be explained by the fact that some signs of a learning disability (especially if they are mild) may be mistaken for a general lack of ability, for example: understanding information, reading and writing, memory issues, etc.  

Getting a timely and accurate diagnosis is extremely important – this way, adults with learning disabilities will have a better understanding why they are struggling with certain things in life and what kind of support they need. Tailor-made support, in its turn, may significantly improve the life quality of persons with learning difficulties by enabling them to participate in suitable education and training, and to find satisfying employment.

The article „Signs and diagnosis of a learning disability in adults” provides information on the number of persons with learning disabilities in the United Kingdom and describes the process of diagnosing learning disabilities among adults: https://www.homecare.co.uk/advice/signs-and-diagnosis-of-a-learning-disability-in-adults.