When should I go to L&D?

So, I’m a repeat c section. Not allowed to go into natural labor. Doctor told me to go to hospital when contractions are 15 min apart,., problem is, usually 15 min apart can still be Braxton hicks, or they might not be too painful at 15 min apart, and how consistent do they have to be before I go??? Any advice?? They don’t want me to wait for them to be closer together. Hospital is 40 min away. Also I never had natural contractions that I could feel before tbh. With my first my water broke and I didn’t have contractions or when I did I barely felt them.