hi,

see you can apply for tet, ctet like exam after passing graduation course in any discipline. however Btc or D.EL.ED stands for basic training certificate and recognize by NCTE, government of India. candidates who wants to pursue career in  primary school teaching profession may apply for this certification course. now the eligibility criteria for BTc course is as follows: candidates must have passed 10+2 course from a recognized education board. so you may apply for btc course after completing your graduation as well.