It’s perfectly normal & natural. Everyone’s experience about night fall or Nocturnal emission is different. Some men have experienced large numbers of nocturnal emissions as teenagers, while others have never experienced one. Some have the dreams only at a certain age, while others have them throughout their lives following puberty. The frequency that one has nocturnal emissions has not been conclusively linked to one’s frequency of masturbation.
Some people experience it frequently while some don’t experience. So Relax ! Don’t worry and Take Care