VBAC uncertainty

I was induced with my son at 37 weeks for pre-eclampsia and had a very rough labor. Pitocin contractions were the worst pain I have ever felt and it last for about 26 hours before I was dialated enough to be ready to push. I was pushing for about an hour and was so exhausted from being up for 2 days but still determined to get my son out! Unfortunately he had other plans and decided to stay right where he was, basically stuck. So off to a c-section I went and everything went fine. I was up and walking by the end of the day, but that's my stubborn dont-need-help personality.

Anywho,

I'm expecting my 2nd at the end of December and I keep going back and forth between a scheduled c-section or vbac. My obgyn said that my success rate would only be 50-60% (although calculators I've researched claimed a better success rate, hmm). Obviously if I have pre-eclampsia again or if there's extenuating circumstances I'd be fine with cesarean, but I don't want to be pushed into it just to appease my obgyn's schedule or because my baby "won't fit". (My obgyn also said my pelvis was too small but I've read that condition is very rare and have never been told I have that condition before).

If I go into natural labor before my scheduled date can I try for vbac or am I only allowed cesarean?