Do you have any idea of the virtual top tube length? I ride a Unisex Titus Racer X in size XS, which I believe is a 15" so probably not much smaller than the Trek you're considering. I am about 5'1-1/2" with a 28.5" inseam, and the bike fits me great. I have always ridden WSD road bikes as mens bikes have too long a top tube for me. The Titus has a short top tube so is WSDish in geometry, despite being "unisex"; I didn't even have to change out the 10 cm stem!j

That Trek is a beautiful bike! If it fits you, I'd say go for it!