By "later on", do you mean on the day of your death? or in heaven?
If your heart is for other things right now instead of God, then your desire to live your life for God is not a pure, selfless desire, rather a desire to go to heaven at the end of your life. Do you long to know God now? Not wanting to live for Him now indicates a lack of interest and love toward Him. That is truly what He wants. For when we love Him, we will follow His commands-- (see 1 John 2:3 and 1 John 5:2 if interested.)
If we wait until it is a convenient time for us, we may lose the chance. (death may come before we expect it) and then you will know for sure that you made the wrong choice.
Besides, what is there in living for self? Sin? Life is so much more wonderful and meaningful when you do live for the Lord God. Sure, you fall, but you can get back up again. His life for you is one full of inward joy and peace and love. There's nothing like it.