I never charted or paid attention to my CM as it confused me & I didn't really know what I was looking for in that regard. I just used an OPK instead as it seemed easier for me. Mine was just one from the supermarket, nothing special anyway.
Got positive on OPK on day 15, DTD that day & day 16. Had also DTD before I got the positive, I think day 13 from memory.
Good luck with getting your very own very soon!!