how much does age difference play

hello I wasn't quite sure where to post this but I'm 23 and my fiance is 42 I know I'm gonna probably get some negative comments but I've done some research about age difference and we've been trying forever and I'm starting to get really concerned that him being so much older I'll never get pregnant we are getting married soon and we really want a family together . I was hoping somebody could help shed some light on the situation thanks so much.