Hi Agnes
If you intend to HWE, just follow Best Practice techniques and procedures and you should be OK. Pay special attention to drying strokes and post clean towelling. Don't be too physically agressive or you could cause pilling. Use Woolsafe solutions. Vac VERY well. Make sure it isn't stuffed with horsehair as this could be problematic, as with any suite.
Water would not normally create any significant shrinkage problems. In the case of garments, it's the agitation that causes shrinkage when fibres facing opposite directions lock the cuticles, They can slide in one direction but not the other. Think of it like two fishes facing one another, they can slide past each other, but the scales lock if they try to go backwards. It's vegetable fibres such as cotton and jute that swell in water, causing the fabric to shrink. That's why a woven carpet may shrink from cleaning, not the wool.
Safe and happy cleaning
Ken