I agree with Donna, I would aim for about 7lb a month. So that would mean roughly about 10 months. Are you hoping to lose the whole 69lb by your 40th? I think it would take longer than 5 months to lose the whole lot, but I'd say you could definatly be into a healthy BMI range by that time. The problem is knowing how quickly it will come off as everyone is different, but as Donna said, a 1.5-2lb loss a week is average.