i really want to get oscp its much more better than ceh but idk how to get starte and i have a question if this certificate is great, why CEH is more famous? Specially in 3rd world countries.
There's a difference between knowing how something is done, and actually doing it. A lot of certs out there focus on how something is done, and quiz you with a multiple choice exam. Don't know the answer? Guess, maybe you'll get it right. OSCP tests you on your ability to actually understand the concepts, and apply them on real machines. There are no multiple choice questions. You either know how to break into the machine, or you don't.
The syllabus on the OSCP tells you what you need to know before you take it. Typically it states that you should have a good understanding of networking. I would also suggest knowing some programming as it will help you focus on the hacking material instead of learning programming as you go along.