Long Menstrual Cycle and TTC

My menstrual cycles have come back (my DD is almost 10 months old) and we would like to have a last baby (if that is possible). I have noticed, though, that my cycles are now 40+ days! I am breastfeeding but my cycles resumed when she was around 7 months old so I don't think I can blame it on breastfeeding. I of course, always think I might be pregnant when I go this long but I am not. Prior to the pregnancy, my cycles were 21 days!  Will a longer cycle affect my chances on conceiving? Do any of you have longer cycles and have conceived? Is there anything I can do to shorten the cycles and thus have more cycles in a year? I am older and we have decided that if it doesn't happen within this year, we will shut it all down because our chances of having a healthy, normal pregnancy and baby are so much less.