Oh I want to have a baby too... like, right now would be nice! LOL
But seriously, there really isn't ever a "right" time. My husband and I have been married just over a year and we had said we would wait a year to start trying. YEAH... that didn't happen! LOL. I got the itch too. And then I also have "issues" and we were told it'd be very hard to get pregnant or to maintain a pregnancy. Well, first month we started trying was October... do the math... and TA DA!
So, what I would do is start saving. Put away a certain amount every month. Perhaps go to the store and calculate how much diapers and formula will cost. Then add on some extra for child care and start saving that now. See if you can do it. If you can, then it should help your fiance's fears ease away, and you can try for a honeymoon baby! Plus, you'll have built up a nice little nest egg that will be awesome for decorating your nursery!