Uy mama, yan likely ang mucus plug na! Ako din nabigla ng ganitong discharge around that time, parang thick stringy stuff lang na walang amoy, and honestly it's a good sign na your body is prepping for labor soon, talo na lang if it's mixed with blood (bloody show), that's usually the real thing na! Since your OB said your cervix is thinning na kahit closed pa, you're definitely on the right track, pero if you're worried or it suddenly changes (like maraming bleeding o malakas ang odor), better mag-check in with your OB para peace of mind lang especially being first-time mom. A few of us tried just monitoring at noting when it happened, pero sa case mo since close pa ang cervix, mas safe na mag-follow up sa doctor na lang para sure.