Hello Ayush,

For IMU CET the dates are as follows -

Start of registration - First week of April 2019

Final date to fill and submit the application form of IMU CET 2019 - Second week of May 2019

For JEE Main -

The Paper-1 of JEE Main 2019 is being conducted from January 9 to 12. Registrations for the April exam will commence from February 8 to March 7. The exam dates of next JEE Main are April 6 to 20, 2019 respectively. 

For more details please visit -

https://engineering.careers360.com/articles/jee-main-important-dates

Good luck!