Why can’t I get Pregnant?

Patient: I am 20 years old and happily married. My 26 year old husband and I have been trying to get pregnant for a year now and so far it has not been a success. We have tried a few tips I read about on the internet, including having unprotected sex daily. I’m not on any perscription medication that could affect this. Other women I know are getting pregnant after only a few months, why can’t I get pregnant?