All children are born with a small hole between the upper heart chambers called a patent foramen ovale (PFO), that can take months to years to close and is nothing to worry about. A very small muscular VSD as you describe also is nothing to worry about. They often close within the first few years of life. But even if they remain open, a tiny VSD would not cause any problems and a person can live a long healthy life with a small VSD.
This is very helpful, thx