I just am incapable of concentrating. how do i show my mom that i have adhd rather than directly telling her?

Get evaluated: By a psychologist for adhd. They may also want you to consider having an evaluation for medication with a psychiatrist once you have the results speak with your mother about what you have learned about your concentration problems. You are an adult now and need to take care of yourself. Hopefully your mother will be supportive when she learns about the doctors recommendations.