individuals with ADHD can join the U.S. military, but it may depend on the severity of the condition and how it affects your ability to perform military duties. Having a 504 plan for ADHD does not automatically disqualify you from military service, but it's important to note that the military has specific medical and mental health standards that all applicants must meet.
A 504 plan is typically an educational accommodation plan, and the military may consider your academic performance with and without the accommodations when evaluating your eligibility. If you have been successful in your academic pursuits and have maintained high averages, that could be viewed positively during the recruitment process.
However, the final decision will be made by the military medical professionals during the enlistment process. It is essential to be honest and transparent about your medical history and any accommodations you have received during the application process.
Keep in mind that policies and regulations can change over time, so I recommend contacting a military recruiter to get the most up-to-date and accurate information regarding ADHD and enlistment in the U.S. military. They will be able to guide you through the process and provide you with specific information tailored to your situation.