If something can come from nothing, then non-existence can be “followed by” existence. This is relevant because non-existence being “followed by” existence is straightforwardly impossible.1
1st Law of Thermodynamics (conservation) says matter cannot be created or destroyed. This is relevant because if physical reality began to exist then, in contradiction to the 1st law of Thermodynamics, matter would have begun to exist as well.
• …It's a law of spacetime; it doesn’t apply to objects independent of spacetime or to spacetime itself.
And so what? Couldn’t it simply be that…
• …It's only naturally impossible—not fully (or logically) impossible.
Causation requires space-time. This is relevant because if causing spacetime (emphasis on time) requires spacetime to already exist, then causing spacetime would amount to self-causation, which is absurd.
• …Time is relational (so causation, a “first move,” can initiate time)1
• …Causation does not require time (causal priority needn't imply temporal priority)2
• William Lane Craig: “classical theological creationists like al-Ghazali (1963, pp. 23, 33, 36) maintained that the cause of the origin of the universe is timeless, and contemporary defenders of divine timelessness such as Stump and Kretzmann (1981), Helm (1988), Yates (1990), and Leftow (1992) also conceive of God's causal relation to the world to be one which involves no temporal succession on God's part, whereas the effect is temporal in its existence.”