Planning to get pregnant

So I've been with my man for 3.5 yrs, and we are very happy. Im 32 and he's 39. I always said I wanted to be married before having kids but time scales with the biological clock ticking and his job in the military mean that we've been thinking we shouldn't wait much longer. Will I regret having kids before walking down the isle? I'm a very practical person so not sure....
Anyway I came off BC in April as we wanted to make sure my body normalises After about 12 years on the pill. 
we reckon we will try in January to get the bun in the oven. I've just started taking pre conception supplements and we are both on a health kick to try and get fit/ lose a bit of weight (neither of us are very big but could each do with losing  a few kilos)
Im trying to come to terms with the idea that's will be pregnant with him away, but if we are lucky enough to conceive in Jan-March, he should hopefully be around for birth and first month or two. Am I being wildly optimistic and unrealistic by assuming  it could happen that quickly? 
Any advice too on being a military wag greatly appreciated!