Hi mama! Don't worry too much, at 20 weeks, breech position is super normal pa lang, maraming babies ang tumitigil pa dyan and nag-flip on their own by 28-32 weeks, so you still have time! Posterior placenta is also walang problema at hindi yan nakaka-trigger ng premature birth, kaya breathe lang. A few of us moms had breech babies around that time and lahat nag-normal positioning by third trimester, but definitely check with your OB on your next visit para ma-monitor mo lang closely and para sa peace of mind mo, they can give you exercises or tips na pwedeng tumulong sa baby to turn kung needed na. Stay positive, mama, you got this!