I found out this year I didn't sign up for selective service earlier, but I'm too old now. Help?

I think my brother. I don’t remember any notices in the mail at all, and I never filled out an FA before. I made the mistake of letting the recruiter I had ADHD and autism, and military is reluctant to take recruits with those conditions. I just don’t want to enroll with possibility of them changing their about the financial aid and expect me to pay out of pocket.