hey pragati,

the eligibilty criteria of CDS OTA is candidate must have completed their graduation or appearing for the final examination ,the age limit is decided to be 19 to 25 years old and martial status can be both unmarried and married and candidate should be a indian ,candidates from nepal,bhutan,and tibetan refugee,pakistan,burma,sri lanka and east african countries of kenya,uganda, the united republic of tanzania,zambia,malawai,zaire and ethiopia or vietnam are also eligible but only after subject to fulfillment eligibility criteria as the rule of government of india

all the best!