Hello Manish,

From the sources i have forund that Thapar patiala is better than GOVERNMENT COLLEGE OF ENGINEERING, Ajmer. The resons for this are:-

• EXCELLENT AND EXPERIENCED FACULTY MEMBERS 
  
• BRAND VALUE OF THAPAR
• GOOD INFRASTRUCTURE 
• GREAT SOCIAL LIFE
• ENORMOUS OPPORTUNITIES 
• AND THE LAST BUT NOT THE LEAST IS PLACEMENT WHICH IS WAY BETTER THAN GEC, AJMER. THE AVG SALARY FOR MECHANICAL IS 3.6 LPA. 

Mechanical engineering ia a really good choice as it is one of the core branch of engineering.

I hope you will find my answer helpful. 

All the best.