it all depends on your body, my sister fell quickly with her first 2 kids but wasn't on depo, she had 2 shots of depo and it took her 10 months to conceive with my nephew. I however was on depo for 2 and a half years and have been off of it the same length of time and have yet to conceive. As you have only had one shot i think your chances may be good but remeber a healthy couple can take from 1-2 years to conceive so don't stress too much. I honestly hate the depo and wish i had never taken it as i feel strongly that this is why i have yet to conceive as all fertility tests are clear. I wish you loads of luck when you start ttc!!