I attended animal mache with a 3-year old. The level of craft skill needed was fine. One important consideration is whether the child is happy to have sticky fingers - inevitable for this, I would say. There was opportunity to clean hands during the workshop but I ended up doing a speedy conclusion to our dinosaur because of the glue.
Having said that this is a craft that offers a challenge to older primary age children - to make it neater than the youngest can manage.
Encouraging instructor.

I attended with my 3 year old granddaughter. My 8 year old grandson decided not to go. The instructor gave me a bag of material for him to complete at home.
It was well organised. The instructor was encouraging and helpful. There were plenty of craft materials. My granddaughter was pleased with the result of her efforts. We shall come again.