13 has pervasive cultural significance, but I agree that 19 seems as "rare" as 17. Perhaps at a glance 19 is less obviously prime than 17. Also note that 17 and 19 are both ages at which nothing really notable happens. 16 is driving age for lots of states and 18 is a big "legal" milestone.
19 is drinking age in most of Canada.
19 feels too close to the nice, round, important 20 to count as properly random for me.
Agreed 17 really doesn't seem to have any significance anywhere in almost any society.