A dictionary definition of a miracle is an "event that’s not explicable by natural or scientific laws and is therefore considered to be the work of a divine agency.” So occurrences outside of natural or explainable forces are considered miracles. If miracles are possible, God seems most qualified to do them.
Scientific methods have posited, but never explained, the origin of the universe. In fact, natural laws didn’t even exist before nature (i.e., the natural universe) began. Therefore the universe requires a supernatural cause, such as God. We tend to take the universe (our habitat) for granted, as fish take water for granted. But its very existence is a miracle.
If God can perform the miracle of creating the universe, God can certainly perform other miracles. Put another way…if we believe in a God who created the universe, we must believe that He can intervene in it and perform miracles.