I had a C-section, and I was told it is unlikely to have a vaginal birth in the future. Why is it so?

Hi doctor,

I want to know what are the tests to diagnose CPD or determine pelvis type accurately. I recently had a C-section and was told I was unlikely to ever have a vaginal birth in the future. My baby was 6 lbs 12 ounces. During labor, I was 2.3 inches dilated and fully effaced when my midwife met me at the hospital at 10 AM (my water had broke 12 hours earlier). Three hours later, I was 3.5 inches dilated and had full uterine activity. My baby was at negative three stationings, had +1 caput and +1 molding, and was suspected to be in the left occiput posterior position (I imagined transverse based on what I felt my entire third trimester). My contractions slowed drastically between 1 PM and 4 PM. I was given an Oxytocin drip and an Epidural at 4:30 PM. Later in the evening, I attempted to push for an hour and a half. The baby was at negative two stationings, had +2 caput and +2 molding. I waited for the OR to open for a c-section. I was given a c-section at 10 PM, and my baby was delivered in the left occiput transverse position. The on-call obstetrician told me that my pelvis would likely not allow for a vaginal birth, and there was no chance my baby would have descended. Is there a way to determine if this is true CPD that would affect future births or if perhaps the baby's position was incompatible with my pelvis shape? Kindly help me.