Can only VBAC before 39 weeks

Jamie

So my after my 28 week appointment yesterday my doctor told me she feels most comfortable with a VBAC if I go into labor before 39 weeks and if I come into the hospital already at 4-5 cm. She is really VBAC friendly but only if I had gotten pregnant after a year of waiting. My son was born Dec 23 2017 and this baby is due Mar 4 2019, so about 14 months apart. She is concerned with uterine rupture and wants to measure my scar thickness at 36 weeks. I had PROM and an induction at 40 weeks with my son and never got past 2 cm with 46 hrs of labor before an emergency c-section. What are the chances I'll go into labor and be dialated when I go into the hospital before 39 weeks? To me it sounds like I'm going to have to get another csec. Very disappointed.