YOU SAID:

Start the party without me, because I am gonna be late

INTO JAPANESE

遅刻するので、私なしでパーティーを始めてください

BACK INTO ENGLISH

I will be late so please start the party without me

INTO JAPANESE

私は遅れますので、私なしでパーティーを始めてください

BACK INTO ENGLISH

I will be late so please start the party without me