Hi LissaLuna,
Welcome to the Mattress Forum! 
There is no single firmness level that is always best for all children and different people or different manufacturers can have different definitions of firmness, but babies and infants will generally need a firm to extra firm sleeping surface while toddlers will generally need a medium firm to firm sleeping surface and older children that have transitioned to a larger mattress and are out of the crib will generally do best on a medium to medium firm sleeping surface. There is more complete information on this subject in post #2 here.
Dunlop latex compresses at different rates for different masses (all products respond to “weight”), and it’s softer initially in the first 25% or so of compression, and then firms up faster (has a higher compression modulus), so the product will feel different to you than to your child, so I wouldn’t use your comfort preference as a basis for what is best for your child. As for a comfort recommendation, I would give a strong consideration to what Sleep on Latex advises, as it does dovetail with generally accepted sleep ergonomic guidelines for a toddler.
Phoenix