Fact: today I am alive on the earth. Tomorrow I die. Again, facts are circumstances that are changeable, etc. etc...
Look at how you state the facts in example, though. You explicitly say you own a particular kind of car “today.” Whatever changes tomorrow, the fact of what you own today remains true forever. Facts are not changeable.
You go on to specify that you are alive “today.” Should you die tomorrow it will still be a fact that you were alive today. That can never change. (Unless, again, God’s omnipotence means he can reach into the past and change facts. I’ve never been clear on the extent of his supposed powers.)