hi,

see if you are really enthusiastic of learning, age is not a bar for you, however nios is acceptable in most of the government and private colleges, so after completing 12th from nios, you can certainly take admission in graduation courses, see if you are from science background you can do bsc courses from open university, you may also go for engineering, but at the end it may be difficult for you to get jobs since some of the psus and private companies have restriction on year gaps and age limit. so the best career  options for you from my point of view  is,

bsc

bba

b.com (//b.com)

b.a in economics or b.a in english