Any psychiatrists on blue light that want to answer this question?
I'm a psychotherapist and can chime in.
What I often see is this:
Biological/genetic type mental health conditions develop through adolescence with a first true break occurring late teens and early 20s, with cycles of high acuity and relative normal functioning that can be anywhere from mostly functional to mostly not-functional. - This is the pattern with with things like bipolar disorder, schizophrenia, schizoaffective disorders
Trauma related disorders are more nuanced as they start with the inciting event(s) and can be pinged up a notch with subsequent events. Dependents on what OP may be experiencing, it would be very reasonable to see a worsening of a trauma related mental health condition increasing in intensity in late 20s, early 30s as this is the time period where there are the least built in supports (school, parents, etc.) and the most areas of vulnerability (relationships, children, jobs, life goals - the sort of make or break stuff that can send you for a loop if you're struggling to be successful in this domain.)
Mood disorders like depressive disorders or anxiety disorders can also follow patterns like trauma related disorders as they can be linked to events throughout our lives that worsen our subjective experience - if I'm constantly stressed about money and I'm anxiety prone, my capacity to manage anxiety will become both better and worse at the same time - I'll probably have less devastating panic episodes, but I'll be a more generally anxious person who is difficult to be around for long periods, heightening social isolation and damaging protective factors like relationships and jobs. We are also fully capable of doing real damage to our life trajectory at this point in our lives, so it can be a period of great vulnerability to mental health conditions that are more experiential in nature, vs. ones that are more thoroughly housed in genetic traits.
The good news is... we tend to right the ship eventually - we learn to live with ourselves as we are. Recovery is acknowledging that we are who we are, and that's okay, that's all we need to be. Just work with who you are as best you can and set goals to make yourself better. The best way to figure out what your goals are? Identify your own values as values are the guiding points for where we want to travel in life and how we want to behave along the way. If you know your values, you can navigate anything in life.