All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
If you have already met the conditions of registration at the university – as we already understand from the question -, there is no blame on you if you continue your study therein and benefit from the certificate it awards you in the future. As for your delay in applying for registration in the due time and using expressions of apology, these are not valid reasons to stop your study and get your certificate. So, keep away from these whispers and doubts and do your best in your study.
Allah knows the best.