My mom said i got diagnosed with a cognitive disability when i was a child what does that even mean?

Translation= at the time you had difficulty retaining information you read/heard/studied at a level expected for your age at that time. Such issues may or may not persist in later life. Not everybody runs as fast as others, some are faster, some slower. This is the sort of thing people may or may not grow out of when older.

Assuming the diagnosis was based on some valid screening instrument, there was a concern that you would be a slow learner. Fortunately with practice many overcome initial concerns. It would be useful to determine the specific concern and how it was assessed.

That is too vague to understand. You would need to know specifically what types of things are difficult for you to learn.