hi,

yes you may get admission in btech in computer science stream. see for nits and iits, admission in b.tech you need to score 75% (general )aggregate marks in 12th exam, for sc/st /pwd it is 65% in 12th in aggregate. but there is many more colleges, for state government and some state universities eligibility criteria is 50-60% marks in 12th exam. see to get a good college you need to apply for entrance test. you may follow the below link to know about engineering entrance test,

https://engineering.careers360.com/exams