help/advice/personal experience??

How long should I TTC without happening before I should worry something is wrong? I'm 31, got married in march (never had sex before I was married), got pregnant in April. We weren't really "trying" but weren't "not trying" either. Unfortunately I miscarried in June and have been trying again ever since. I'm a little worried since I am a little older. Can anyone help me here. The dr said she wasn't too concerned with my MC since it was just the first. I just wanna be a mom really bad. I know we've only been trying for a few months but I guess I was thinking it might be quick because it was the first time.