There are a couple of entrance examination that are there for admission to B.Tech courses in India. For example, JEE Mains has no minimum aggregate criteria unless your target colleges are NITs, IIITs and CFTIs. You can appear for JEE Mains or your State Level Entrance Examination for admission to B.Tech. For example, it is GUJCET for Gujarat, AP EAMCET for AP and TS EAMCET for Telangana. So even with 58% in your 12th you can still appear for JEE Mains or relevant State Level Entrance Examination and secure a seat in B.Tech in CSE.