This report of placenta is absolutely normal. I guess your baby’s heartbeats and growth have documented by ultrasound to be normal. The grading of placenta depends upon the sonographic morphology, with grade 3 indicating a mature placenta, usually at term. Sometimes one comes across a grade 3 placenta earlier on e.g. at 32 -34 weeks, when a woman has hypertension etc, which then becomes a point of concern to the obstetrician, as it then indicates premature aging of placenta - to describe it in simple lay mans terms.