It's not safe to be a child. A nun advised my family to let me become a monk, or I would die. What is the reason?

This is a fallacy. Knowing what is right is wrong. Life, which family you were born in and who your parents are, this is life. But luck will change, things are impermanent, impermanence is good, it may get worse, and it may get better. It depends on what business you have established. Want to be healthy, release more, do more good deeds, plus doctor's treatment, good attitude and exercise more. Read more Buddhist names, Buddhist scriptures and the like when you have time, and repay all the unjust creditors in your life or even this life. I believe your health will get better soon. Believe in yourself. Buddha said: Buddha does not measure people, but people measure themselves. The buddhas and bodhisattvas just told us a way to get rid of our sufferings, and we still have to go by ourselves. Buddhists, bodhisattvas or monks are just our gifts. Don't be superstitious, you will harm yourself and misunderstand Buddhism.