Since everyone reacts so differently to meds and drugs, I'm not sure my experience will help, but I was on the depo for a VERY long time back when I was about 19-28 or so. I got off of it when I got married and I had ZERO side effects.
I am now back on it (have been for about 6 months) and again no side effects.
However, I'm the type of person who rarely gets side effects from drugs. Good luck!