Hey Bharat!
Engineering is a something so very versatile that it encompasses many fields. Both aerospace and computer science engineering are two of the highly technical fields with good scope in future.
In computer engineering, you study primarily study about programming. If you have a good logical sense and an urge to develop softwares and study about the internal working of the computer, then you will surely enjoy CSE.
On the other hand, if you are fascinated by the working and the development of aircrafts and spacecrafts, then aerospace engineering is the one for you!
Comparing the difficulty of the two fields does not really hold any significance as both require equal amounts of dedication to excel in.
It completely depends on what you would prefer. Because if you choose something that you don't really like, then no matter how much effort you put in it, it will always seem difficult.
Good luck!