C Programming Language

I'm trying to create a dynamic array which can be modified using the functions Array_Push(array, val) & Array_Del(array, index). Now the current way I have this I need a variable to keep track of the size of it. My implementation of this concept is to store the data/size in a struct like so:
 struct Array {
  void **data;
  int size;
 }
However in order to read the actual array you have to type array.data[i] which I think is a little bit redundant. My solution to this was attempting to store the size of the array in a different index. I didn't want to store it inside [0] as that would create a lot of confusion, so I wanted to try storing it inside of [-1]. An obvious problem with this is that [-1] is outside the array. What I did instead was create an array via void **array = malloc(sizeof(void*) * 2) (the * 2 is so when you push with realloc() it doesn't free empty memory,) then setting the size via array[0] = (void *)0. After that I increment the pointer to it via array += 1. However when I try to free it free(array - 1), I end up freeing non malloc()ed. I think this is just an issue with my understanding of pointers, so I wanted to ask where my logic is going wrong, along with if anybody actually knows how to do what I'm trying to do (in the title).