Depo shot and pregnancy

Just been in my first shot and decided I don't want it again
I know it's in your system even after the three months you supposed to get another one 
But read up online that people were diagnosed with pcos
Was wondering if any of you guys have been on depo and stopped to have a baby and have succeeded inbecoming successful even if it took ages!
I'm only 20 but want to have a baby someday!