If it's never been cleaned in 17 years, then it's at least 17 years old.
Since it is secured flush to all 4 walls, any shrinkage will pop it off the tack strip and possibly split any seams.
You would most likely want to check the backing to see if it is Jute, which seems to be common on older wool carpets. It is the Jute backing that will shrink when wet and cause big problems.
I ran into some wool w2w recently that I did not think would be a problem because it did not have a Jute backing, but for some reason it shrunk back a little, so be careful. Seems that another backing component may have been susceptible to shrinking when wet in this case.
Some here will say thy wet wool w2w all the time with no problem, and I too believed it until I almost made a very expensive mistake, so be as cautious as you can, and try to do your best in identifying exactly what materials you are wetting.
