Two things: it depends on whether there is wording in the newer law that specifies that it supercedes the older law, a and when that takes(took) effect. If the law at the time of Obama’s birth stands, how old was his mother when he was born?
Mamma got knocked up at 17.
Had Barry when she was 18.
had to be 19 under the “naturalized” rules in place at that time- 1961.