Sometimes it takes a while for a couple to conceive...its just hit or miss really lol. but may i ask why you want to have a baby at this age? I know i am dying to have a baby but im only 19 and i want to wait til im through with uni and been in work for a year.
Not pointing fingers and telling you that you shouldnt do it lol, just curious..
try not to have sex so frequently like wait 3 days after each time you have sex you could also count 14 days after you get ur period and you'll have a higher risk in gettin pregnant goodluck
Two possibilities:
1.) You could have scar tissue or fibroids lining your uterus, preventing a fertilized egg from attaching to the wall.
2.) The man you're sleeping with could have a low sperm count or be sterile.
Go to the doctor. That's th only way you'll really find out.