Yes, you can take admission after your 12th class.

Below is the eligibility criteria through TNEA exam

- You should qualify 10+2th standard (or equivalent) examination with the required minimum average aggregate in the subjects of Physics, Chemistry and Mathematics.

-General category applicants will have to score 50% aggregate in 10+2th standard (or equivalent) exam for backward classes it is 40%

- You should have domicile certificate

You can check the cut off the colleges from the given below link

TNEA Cut off

Good Luck!!