the best indicator ime is how you feel and how you think the movements of the baby are.
i went overdue with all mine, term plus 18 with ds3 well a bit longer than that by their dates! i did go and be induced with mine from term plus 15 to +18 with ds3 as i was FED UP and with dd i went in at term plus 10 as i KNEW i would still be there 4 days later and also because i had had a lot of stress with ds3 having kawasakie disease and being unwell myself and i had a niggly feeling, not sure what but actually i was low on fluid levels which was never an issue with my other 4.
all mine were vernixy and yes big but the placentas all looked fine the midwifes checked them over and i had a good look and they assured me they were fine a placenta that is starting to 'go' looks a bit gritty? or somehting they said.
if you are concerned get monitering and you can ask for expectant management and a scan to check the blood flow from the placenta etc, i had that with mine, they were a bit stroppy about it, but you are allowed to request it.
i had it in lovely big red pen on my notes PATIENT HAS REFUSED INDUCTION AND HAS BEEN INFORMED OF THE RISKS OF STILLBIRTH! nice! that was with ds3, who was 3 wks over according to hospital dates, not quite that much by my dates.
i tried everything to get my 5 out, lots of sex etc, what did help was accupuncture, lots of contractions and a show after that i could feel it working whilst the woman did it.
fwiw if you do get induced it may be ok, as i was ovedue with mine and alreayd 3-4cm etc they just broke my waters and i then laboured fine, had ds4 in the pool in under an hour.
interestingly the baby i didnt wait till AT LEAT 14 days over for, dd i ended up with syntocinon, i suspect had i waited a few days i wouldnt have needed that tbh, but as i said i had circumstances that made me concerned so it was the right thing and my labour was still active, just gas and air and fairly quick :)
when i had ds1, and ds2 and ds3 the policy was term plus 10 by the time i had ds4 is was term plus 14, it varies depending on where you live! and with dd i ahd to request induction at term plus 10, they were happy to do so as she was no 5, so technically higher risk and because my fluid levels were low, there werent so happy that i refused constant monitering and had an active labour on a birth ball etc, well the consultants werent, the midwife was fine :)
good luck, they may try scare tactics to pressure you but do your research and fingers crossed baby puts in an appearance asap :)