Hi Pumpkintomyself,
Welcome to the Mattress Forum!
That’s great news – glad to hear it.
Growing children require good support, and for a 10 year old I’d generally lean toward a medium/medium-firm surface comfort. This doesn’t have to be a surface that feels very hard, but if your parents require a bit more surface plushness (and of course you could determine this after they visited and gave you their opinion of the new mattress), you could provide some extra plushness with a 2"-3" latex topper. I’d recommend latex versus memory foam or polyfoam for ease of repositioning (better resilience), which can be more challenging as we become older. Otherwise, the same guidelines would apply as presented in the mattress shopping tutorial.
Phoenix