re: Question about early signing period?

not necessarily. usually the recruits who are eligible for early enrollment will also sign in during early signing period since they plan to enroll in January - prior to the Feb nat'l signing day.

But you don't have to be an early-enrollee to sign early.
If you don't qualify to enroll early but also don't want recruiters from schools you aren't interested in continuing to pester you with phone calls for another 2 months or you just want to close the book on your recruitment, you can sign in December and get it over with.