Assume the defined benefit plan has a 3 - 7 year graded vesting schedule and the plan's stated normal retirement age is age 72. The plan as an age 21 + 1 year service requirement, with dual entry dates on the January 1st and July 1st after satisfying both requirements. P turned age 65 on her Dec. 31, 2019 date of hire and is age 66 at her date of participation, January 1, 2021. Assume she always works at least 1,000 hours in a calendar year, which is the 12 month period used for vesting service. At what age does P become 100% vested?