I encourage you to go ahead and do this (perhaps with advice from your pastor) -- not so much for your sake, but for the sake of your children. The Bible says that "a prudent man gives thought to his steps" (Proverbs 14:15).
Remember: The death of a loved one is often a very stressful time for those who survive, and knowing the wishes of their loved one can remove some of that stress. It also can help avoid possible conflicts between survivors. In the Old Testament, we read that Abraham purchased a piece of ground as a burial plot for him and his wife, Sarah; years later, his grandson Jacob instructed his children to bury him there also, which they did (see Genesis 23:1-20; 50:12-13).
Perhaps you're like many people; you don't want to think about your own death. It's the reason some people put off making a will or dealing with other end-of-life legal issues (which often leads to difficulties for their children). But someday you will die -- and what you do now to prepare for that day can be of great comfort to your loved ones.
The most important thing you can do to prepare for that time, however, is to make sure of your relationship with God. Someday you will stand before Him; are you ready for that day? You can be, by turning to Jesus Christ and trusting Him alone for your salvation. Jesus' promise is for you: "Whoever lives and believes in me will never die" (John 11:26).