I agree with the concensus here that it doesn't matter what time of day you exercise but the important thing is to exercise daily...
I always thought that once I reached my 40s that I was doomed to be the weight I was at...NOT!! I will be 49 in a couple of weeks

... What has helped me tremendously in the last couple of years in losing the last few pounds is eating 5-6 mini meals at regular intervals throughout the day, each meal consisting of a carb and a protein and with 2 of those meals lots of vegetables...
Weight training also speeds your metabolism up. I have been weight training for 20 years

... Lifting heavy keeps your bones healthy and the extra muscle also burns fat... I also always lift heavy because it's only a myth that women will bulk up, we do not have the testostorone to bulk like men do... To paraphrase a friend's husband: "If it were so easy to get bulky don't you think it would be easier to get toned, so why aren't all women at least toned"... So, kitgyrl, if you are not lifting weights I would hightly recommend that you start, it will DEFINITELY keep you young!!