I agree with this statement, but it's looking for spermathecae(assuming it's unknown).
Also, telling the age of Ts without actually hatching them from eggsacs is impossible, especially with Grammostola rosea because these are abnormal Ts(to us humans) that grow at very different rates. Awhile back there was a thread where someone(I believe it was one of the mods) had 7 year old slings around 1" of this species, and there is another member that raised a G.rosea from a sling to sub-adult in under a year. There are just way to many variables involved in this, temperature, feeding, etc.
If I had to venture a guess of the sex, I would say male from the picture. I'm basing my guess on the distance of the book lungs from eachother, and the half moon shape of the concentrated hairs and the dot in the middle.