Dear aspirant hope you are a doing well..

As my opinion it's not a good idea to prepare  for both at the same time, I suggest that once you clear your D. U entrance examination and take admission in law college of delhi university, then you have sufficient time to prepare for the CDS exam, As I know many of the engineering student / b. Tech students prepare for the UPSC simultaneously the Accademy session. So you may also prepare for the CDS examination simultaneously with your Academic session.

DU LLB COMPLETE DETAILS

https://law.careers360.com/articles/du-llb/amp

CDS COMPLETE DETAILS

https://competition.careers360.com/exams/cds/amp

hope it's helpful

thank you

Greetings!!!

Being aspirant of two difficult exams it is really hard to handle study but it is not impossible.there are some similarities between both the exams you can take advantage of it.english,current affairs,maths,general knowledge and the only difference is legal aptitude which you have to study for your legal entrance exam.you can plan your study with these tips

Du strategy plan and tips

https://law.careers360.com/articles/how-prepare-for-du-llb/amp

CDS tips and strategy

https://www.google.com/amp/s/competition.careers360.com/articles/how-to-prepare-for-cds/amp

This links will help you in achieve your goals

Have a good day!!