I'm 31 years old, i'm 153cm,59kg. My SYS/DIA is alsway low about 106/65, is it normal?

Normal blood pressure is < 120/80, therefore this is normal as long as you do not feel lightheaded. Lower blood pressures are ociated with a reduced risk of future health problems, such as strokes and heart attacks. Petite individuals like yourself tend to have lower blood pressures. As long as you feel fine, then do not worry about it.