Your company is registered in March 2017. So, you can opt to have first financial year for period of 13 months and in that case you need not to file ROC returns for 2016-17.
You need to file your ROC forms for 13 months and due date is October and November of 2018, so you need not to pay any penalty in case of ROC forms.
However you should have filed IT returns for FY 2016-17 and now online option is closed for FY 2016-17. You need to file application for accepting belated return.