FWIW, we have never had to produce an NDCA number for syllabus am/am or student/student. (Usually around here syllabus is usually just student/student events at NDCA, but that may vary at different comps.)
Another bit of advice for making the most of available floor time ... for USA Dance events you are generally allowed to register for two age groups, your own and one younger for older (senior level in their age categories) adults.
(There is an exception at the "adult" level, as this level is not allowed to dance down to dance against the younger kids, nor allowed to dance up against older (senior age category) adults.)
So if you are at least Senior 1, I would encourage you to enter both allowed age groups. You will get double the floor time, and you may get to dance against some different dancers. (Sometimes you it is just another round against the same folks who are also doing two age groups, just depends on who registers.)
And I would say in general, don't be afraid of contested entries. It is fun being out on the floor with your peers. At USA dance at least, many times the other couples will be friendly, you can chat a bit in the on deck area, etc. And if you go into your first comp worrying about how you dance and not how you place, the placements don't matter anyway. The experience is the important thing.
Good luck with whatever you choose. Let us know how it goes!