In the 18 century BC, death penalty was used at first time,
It probably goes back much farther even than that.
Until now, this kind of punishment is still used in most of countries in the world.
"Until now" and "still" don't work together.
People are born by God, and God is only person who has this right.
Avoid this. It is an unconvincing argument, as it can never mean anything to anyone who is not religious. Also, any person whose religion includes the Old Testament as a holy text will find plenty of permission from God to put people to death at the slightest provocation.
It will be inhumane if government uses death penalty for her.
Why? You assert this. You don't prove it.
In fact, we can see that the number of crimes is rising in some countries although many criminals are punished by death penalty and this kind of punishment cannot stop crimes.
Again, it would be nice if provided some actual facts to back up this assertion.