MrsLA im sorry to hear your husband has problems with depression, that must make things very hard for you. It can be hard enough getting a guy who doesnt suffer depression to agree to have a baby, its taken me 5 years on and off harassing my husband to get to a point he agreed the time was finally right.
It will be up and down for you while you are on the journey but as long as you can talk through your problems you should be fine. I doubt waiting will make any difference as depression is pretty unpredictable, just be prepared to work through his feelings as they change?
I have always been told the 1st day of red blood is counted as day 1 and I just googled it and it said the same thing?