Meri 12th class me science se 318 number hai our mene nrec college me b.a me registration ker diya hai kya meri merit lag jayegi

Yes, your admission is possible. Since you have scored 318 marks in 12th Science and have already registered for BA at NREC College Khurja, your name can come in the merit list. NREC College prepares the merit list based on 12th marks and subject combinations. Science students are also eligible for BA, so there's no issue in that. But final selection depends on the cut-off for this year, which can vary.