Last year I was given one of those "thank you for 30 years of loyalty" cards by a GS rep at SEA on my anniversary. I leaned in and said quietly to her "the fun part is I'm 31 years old!". Grateful to my parents for the foresight and you better believe I will be following suit.
^
My hope is that when they graduate high school, they will have enough miles to enjoy a hell of a gap year traveling the world. Both of my kids had their MP numbers before their SSNs, so this was borne out of my experience. Priorities!!!