I was dx'd with Major Depressive Disorder at 14 years old after a suicide attempt then I did well for a year and stopped treatment and did okay till I was about 16 and then things started getting bad. I didn't go back to a psychiatrist until I was 18 as a last resort and I was diagnosed with Bipolar type 1 with psychotic features which then was updated to Schizoaffective Bipolar Type a few months later after my doctor observed that the psychotic symptoms were also occurring outside of manic and depressive episodes. I'm 24 now and that's still my diagnosis. I think it's common for people's diagnosis to take time. for example when I was diagnosed with MDD it was based on the fact that I was seen during a long severe depressive episode and I didn't remember or talk about the mania because I didn't know what it was and at the time it wasn't so bad that it was causing major issues in my life but it progressed by time I was in my late teens.