I'm new to glow but have tried other apps before this.  I'm almost 24 and my husband is 25.  We have talked about having children forever but never really tried to conceive.  With that being said for the last year and a half we have not prevented getting pregnant. I've never been on the pill, we do not use condoms, and my periods are regular.  I'm starting to get concerned I'm just not fertile.  How should I wait before going to a doctor?