Without wanting to be dramatic, for me the question was, would I prefer to not have another child (because I waited too long) over having a gap that might not be ideal for first 12 months. It took me so long to have #1, I wouldn't have cared. It ended up being 22 months which I found was fine, but still took 6 transfers which if I hadn't done almost back to back, it would have taken me much longer. Do what your heart (and a bit of your head!) says.