Ay, that's such an exciting time, mama! Honestly, the mucus plug can look different for everyone, sometimes it's thick and stringy, sometimes it's more like a blob with a bit of blood (the "bloody show"), so it's hard to say for sure without seeing it yourself, but if it's gooey and kind of clear to yellowish, malaki ang chance yan na talaga na siya, lalo na at sobrang lapit mo na sa due date mo. Best thing to do is message your OB or go to your hospital para ma-check nila and ma-monitor kung may contractions ka na or if labor's starting, kasi 39 weeks 5 days ka na, and they'll know better what's happening with your body.