Q. From what age on does one have to give the Machatzit Hashekel. Bar Mitzva or Twenty years old when they were actually counted on those days?
A. Rema (O.H. 694: 1) rules that only one that is twenty years has to give the Machatzis Hashekel. However, Mishna Berura (ibid 5) quotes opinions that even after Bar Mitzva one has to contribute.
He also quotes Eliahu Rabba that the tradition is to give even for children and for a pregnant woman.
Rabbi A. Bartfeld as revised by Horav Dovid Pam, Horav Aharon Miller, Horav Chanoch Ehrentreu Shlit’a and Horav Kalman Ochs Shlit’a.