If you have received a denial letter from Social Security, you need to appeal that denial within 60 days. Often getting the denial letter in the mail sparks the search for a Social Security lawyer to help with your claim. But do not lose sight of the 60 day deadline.
The appeal period is always 60 days, at every level of the review process. Whether you receive an initial determination, a reconsideration denial, or an administrative law judge decision, your deadline for an appeal is 60 days from receipt of the denial letter. The SSA will presume that you received the denial 5 days after the date of the letter, so you have an extra 5 days if needed.
But there is no reason to wait. Appeal that denial right away, and get to the next step of the process. Don't give up! And don't waste valuable time trying to make sense of the language in the Explanation of Determination - those explanations are often wrong and sometimes misleading.