as Ztini said: experience beats certification. if you do want to take the exam, there are no guarantees whatsoever.
the only thing you can do is:
- know the material covered by it
- prepare for the exam (for instance: don't keep camming until 5am the day you're going to take it)
- take the exam and take your time for it. don't rush through the questions. faster completed doesn't mean the results are better.
depends on the situation: if you're between projects, it's better to get certified than to do nothing, but if you get the chance to start at a project, don't let it go just because you could get certified.