Hey,
Well,Yes you can go for UPSC examination after getting into NDA. The basic eligibility criterua is that the candidate must hold a graduation degree in any discipline recognized by the government of India. The candidate must be a citizen of India and must be atleast 21 years of age and the maximum age must be 32 years. For Scheduled Caste and Scheduled Tribe,a relaxation of five years is given.
Hope this helps.
Good luck.