Looks like I was wrong (there are 3 subspecies)
http://www.jacksonschameleoncaresheet.com/
The Standard Jackson's Chameleon (Chamaeleo jacksonii jacksonii) is the rarest subspecies in the US. They are from Kenya and reach a total length of approximately 10 inches. Males have three horns while females can have a single horn on the nose or three like the male.
The Mt. Kenya Yellow-crested Jackson's Chameleon (Chamaeleo jacksonii xantholophus) is the most common subspecies in the US. This subspecies is originally from Kenya but has been introduced to various places in the US, as previously mentioned. They can reach a total length of up to approximately 14 inches. Males have three horns while females typically have no horns but have been known to exhibit a single horn on the nose.
The Mt. Meru or Dwarf Jackson's Chameleon (Chamaeleo jacksonii merumontanus) is a fairly readily available subspecies but not as common as Ch. j. xantholophus. This subspecies is from Tanzania and reaches a total length of approximately 8 inches. The males have three long, narrow horns while the females have a single horn on the nose. This species typically has bright yellow crests.
i'm guessing this is the yellow crested. Doesn't look like yours but maybe that will change with time!