Hi brocktoon,
There are some general firmness guidelines for children in post #2 here. 28 ILD would be “soft” for a support core but would be in a “medium” firmness range as a sleeping surface so it should be fine if your daughter is smaller and lighter than average.
It would certainly be durable enough to last for 10 years but it’s not really possible to predict what she will do best with in 10 years because it will depend on her body weight and weight distribution, her body shape, her sleeping position or positions, and her own individual preferences.
The odds that she may need or prefer a softer topper as she gets older and develops more adult proportions would be higher with the “medium” mattress than it would with the “soft” mattress.
There are many other options for children that are discussed in the topics that are linked in post #2 here but I don’t know of any other “all latex” options that are in the same budget range.
An mattress with a latex support core will generally do best with a firm, flat, and evenly supportive support surface underneath it that has minimal to no flex under the mattress and for larger sizes with at least one center support beam that has good support to the floor to prevent any sagging in the middle of the mattress. The components (either a steel or wooden bedframe with a foundation/bunkie board or a platform bed) need to be strong and durable enough to support the weight of the mattress and the people sleeping on it without some of the parts bending, sagging, shifting, or breaking with extended use. The support surface under the mattress (which may be a solid surface, slats, or a steel or wire grid) should have enough surface area to prevent the mattress from sagging through any gaps or spaces in the support surface over time but ideally still allow some airflow under the mattress. If the support system under the mattress has a slatted surface then I would suggest that the gaps between any slats are no more than about 3" (with 1 x 3 slats) although less than that would be better yet.
I can’t see the specifics of the bedframe that you linked so I can’t make any meaningful comments about it but I would make sure that it has at least 5 wooden cross slats so that it can provide good support for a bunkie board. I would also make sure that any bunkie board you are considering has slats that no more than 3" apart.
A solid surface bunkie board that doesn’t have any slats would also provide suitable support but it won’t allow any airflow under the mattress (see post #10 here).
Phoenix