Buddhism says that a person's life is a past life before the age of 30, and this life after the age of 30. What does this mean?

Before the age of 30, your appearance, study, career, etc. Are the fruits of good and evil in your past lives. For example, some people were born in a rich family, and some people are particularly beautiful, which shows that he made a fortune in his last life and got results in this life.

However, in these 30 years, people not only got the results of previous lives, but also did a lot of things, both good and evil. These good and evil karma often bear fruit after the age of 30. If the blessings in previous lives were great, but there were many bad ones in the first 30 years, their blessings would be greatly reduced, thus changing their later lives. or vice versa, Dallas to the auditorium

That's probably what it means.