at around 37 weeks gestation grade 3 placenta can be seen, if the baby's condition, weight, parameters and amniotic fluid
etc are in normal range no need to worry,
you can follow with regular checkups, twice a week non stress test
monitoring till expected date of delivery,
if you have any other complications like pregnancy induced hypertension
, fetal growth retardation etc along with placental factor then early induction may be indicated.