Hey abhinav,

Marks of XII matters only when you get a qualifying marks in there admission process exam. 

To get Computer Engineering (COE) you need to have 96.3876067 to 90.8935359 in JEE Mains

Or according to ranks and marks:

COSE Computer Science 

Cutoff for Punjab: 88260 

Marks cutoff for Punjab: 83 

Cutoff for Punjab: 29595 

Marks cutoff for Punjab: 129

All the best