Course/outlook of bipolar spectrum disorders and cause for concern?

Has much research been done on the course and outlook of bipolar spectrum disorders?

For instance, if I've had depressive tendencies since at least the age of 11, definitely 13, with actual bouts beginning at 14 or 15 and some signs of hypomania or at least very brief elevated moods and increased, longer lasting irritability at the same age...

The depressions I think have increased in frequency and severity but not the hypomania-like symptoms.

My question is if it can still exacerbate at 24, especially with going off to college out of state. Or is there less cause for concern since my brain is mostly or just about finished developing?

I've read that the average age is 25 but I'm not sure if that means the most common age or if that means if, in a study, they took the sum of people's ages and divided by the amount of people.