The Twenty-sixth Amendment (Amendment XXVI) to the United States Constitution prohibits the states and the federal government from using age as a reason for denying the right to vote to citizens of the United States who are at least eighteen years old.
Twenty-sixth Amendment, amendment (1971) to the Constitution of the United States that extended voting rights to citizens aged 18 years or older.
Just compare the notes you took to the information in your research and write the comparisons. I can’t see your notes nor the online research you did so I can’t help very much. Good luck!