No, that's not true. It is midnight after eleven o'clock, that is, the next day, but not counting 23: 40 the next day. But in the first hour of the next day.
There is a theory that it is a matter of time, but this statement is unreasonable. For example, New Year's Eve is the coming year, but the constellation is not based on this, but on beginning of spring, and the coming year is after beginning of spring. Just like this, it is not based on 00: 00, so after 23: 00 is the first hour of the next day. In other words, being born at 23:40 on February 8th is the same as being born at 00: 30 on February 9th.