In the year 2008, 317,283 US people aged 25-34 died, all causes.
In that same year of 2008, 241,740 US people aged 15-24 died, all causes.
The population is higher now.
In 2020 there were 3.4 million US deaths. Total. All ages.
A few hundred thousand at younger age is normal. The majority of deaths is 65+, but it’s not overwhelming, like 95% or something.