First off, I would need to know her size but I highly doubt shes 14 months old. They grow fast, but I still doubt it.
Second, you have absolutely nothing to worry about. Thats a typical Theraphosa spot on her abdomen due to hair flicking and leg rubbing when "cleaning" themselves.
The color of the skin underneath as well as the overal color shows no signs of premolt (At least not coming any time soon). The brighter and the more red the skin appears, the "fresher" they are with the molt cycle.