If you won't choose Him now, what makes you think you'll choose Him later? The longer you go without God, the harder it will be for you to come to Him. The longer you sin, the harder your heart will become and the further from God you will be (Heb. 3:13). To wait is to invite damnation. God calls you to repent from sin now, not later. Which will you choose?
If you say that you will choose Him later, do you admit then that you need Him now? If so, then why do you wait? You might die soon, and then it would be too late.
What if you die before you choose Him?