Should I sleep with someon on first date?

Not a good idea. You should know a person well before getting intimate.
Do you know that. Person's sexual history well enough to know if they have a sexually transmitted disease? Do you know the person well enough to know if you want to be with them over time (vice a possible one night stand?) will you respect yourself if you have sex on the first date? Will the other person respect you if you have sex on the first date? Could this negatively impact your reputation? Ask yourself this.