There are versions of A. desmettiana that have teeth, but that said, the leaves and the openness of the rosette look wrong for Agave desmettiana, as does the terminal spine, which are not that gigantic in A. desmettianas I have seen.
I do not have a real good alternative ID to suggest, one guess: it could be a really floppy A. salmiana, how much sun does it get?
