Not necessarily; teenagers are 1) still under parental health insurance and therefore can get medical care, 2) broadly have adults looking out for them in a way adults don't look out for other adults, 3) are capable of self-introspection and increased communication capacity as well as self-identification in a way children are not, 4) have the agency to advocate for their mental health needs in a way children cannot..
Broadly if we are going to respect mental health more, the one cohort that is broadly capable of receiving mental health assessment medically, has enough agency to introspect to their own mental health, and still generally have adults responsible for their wellbeing, aka teenagers, are most likely to reveal this.