Can it ever take a little longer than 14 days for the second dose of pfizer or moderna to kick in?

It could. 14 days is the average. Though you probably acquired some immunity from the first dose and should not be concerned about a few days this way or that way following second dose. For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, drink enough water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs. Get HPV vaccine.