Dear Student,

No, it won't affect in any matter as there is no age limit to pursue B.tech, any person can pursue this.

As you have taken drop of 2 year so you need to create the gap certificate to take admission in any colleges and you can take admission in B.tech course either by direct or by giving the entrance examination.

In the placement round they only ask you to show the details of your previous semesters, you will be only be eligible to sit in the placements after your 3rd year, they won't ask you that why you have taken break after 12th and it doesn't even matter in placements.

As you got good marks in your 12th so definitely you can take admission in some top private colleges like JIIT Noida, Thapar University, SRM, Amrita School of engineering etc.

Good Luck :)