Counting fingers (or other items) isn't a positional numeral system, so it's really apples to oranges. Also, "first" has a meaning of "nothing precedes it", which is separate from the indexing system", it shouldn't mean "at index 1", unless otherwise specified.
Though the idea of an index as a position instead of an address is weird to me, you can indeed make that analogy.
The "first" element of an array has the index zero, as in "zero elements precede it".
