Barron turns 13 on 13/13
"Barron William Trump" = 91 (Full Reduction) the 13th Triangular
Wed, 20 March 2019 = 13th of Adar II, 5779
י״ג בַּאֲדָר ב׳ תשע״ט
Parashat Tzav (in Diaspora)
Adar II is a leap year month that makes it the 13th month.