Where do I go

So I had an emergency c-section 3 years ago will be 4 this coming March and my due date is May 3rd I have a vertical scar on the outside but I don't know what kind of cut they made on my uterus and I'm really wanting a VBAC and heard the only concern they have is that scar on the uterus not the outside (I may have heard wrong I'm not sure)

My question is how or where would I go to find out what cut they made on the inside? Do I go to hospital or can I ask my obgyn? I feel like it's the hospital but I just wanna be sure I'm right

Also can someone please tell me about VBAC

Edit: I have the low vertical scar sorry I thought I had put this in the comment