Why my body jerk when im starting to fall asleep.. is this normal?

Normal: These are normal and referred to as hypnagogic jerks. When you have these same types of body movements just prior to awakening they are called hypnopompic jerks.

Sure is!: t is very common, esp. if overtired. No risk, as long as you are not in class or hammock! There is also a very common phenomenon called hypnagogic hallucinations: When we are falling into deep sleep, we can experience very vivid dreams and even jerk suddenly, so hard it wakes us completely up. During this phase, you might believe you hear things, and sometimes dream that you cannot move.