Is it unhealthy for a 13 year old to be recently a super in tampons?

It's not exactly a good idea for a 13 year old to be using tampons to begin with, even if you're responsible enough to use tampons correctly as you have thinner vaginal tissues and less likely to have TSST-1 antibodies the risks of TSS are far greater than in adult women.

Teens can have heavier flow due to hormonal imbalances, super absorbency also aren't the most absorbent absorbency. You should be changing tampons every 4-6 hours, if the tampon leaks within 1-2 hours use next absorbency up, if you're already using highest absorbency (ultra) and leaking within an hour then talk to your doctor about investigating the cause and taking medication like Tranexamic Acid to reduce your menstrual flow so it's less problematic.

Consider switching to menstrual cups, these are far safer than tampons so no risks like TSS and thus can be worn for up to 12 hours, with any flow, overnight, before your period, and no need to alternate with pads so a lot more convenient, especially with heavier flow. Menstrual cups can reduce flow, hold a lot more flow than tampons, and don't leak like tampons so easier for heavy flow.