How to save a pyramid into array of chars?

I need help with checking if the position in array must save ' ' or '*' for later in program to print out a pyramid.

At the moment I get out something like this:

This is my code for filling the array:

for (int i = 0; i < t.GetLength(0); i++)
        {
            for (int j = 0; j < t.GetLength(1); j++)
            {
                if (j == t.GetLength(1) / 2 || j == t.GetLength(1) / 2 + i || j == t.GetLength(1) / 2 - i)
                {
                    t[i, j] = '*';
                }
                else t[i, j] = ' ';
            }
        }