What's a great score for any NCSA event? I have a score of 28 objective points. Is that good enough?
What is "good enough" will vary based upon the NCSA and how many applications versus available slots. NCSA's with a large number of applicants and few slots will be the most selective. Some NCSA's have special requirements beyond the objective ones.
Per http://ncsas.com/faqs/, there are 60 points total so you are half-way to the max, but do not let that stop you from applying to as many NCSA's as interest you. You don't get chosen unless you apply.
Depending upon the wing, there may be a review board process as well for cadets to be "green lighted" which is also explained at the link above.