He, he, ..congrats on the BFP AND the 28 year old !!!

Besides the obvious chromosome risks, i wouldnt say 40 was too old. Women these days are having children later (in their 30's) compared to my parents day when 19 was the norm. I suppose the ole bod isnt as crisp as what it used to be when you were say 21, but its mind over matter, if you feel you can do it, go for it !!!