First of all, be calm, Yes you can change your career if you wish.

If you want to pursue medicine you can try for NEET  for medical lines. The details of the exam with all its aspects and scope is available in the link given below.
https://medicine.careers360.com/exams/neet

The age limit for Unreserved candidates is 25 years.


And if you want to pursue any other passion of yours.
Please explore the world of CAREERS360.

Best of Luck My friend.
Life always gives second chances, just take it.