Awww, so glad I could help Steph!
Age definitely plays a part in weight loss, i.e. the older you get, the harder the weight is to lose (and usually the more you put on too). But in all fairness you've gone through a lot of stuff with your body in your life so you have some factors against you as well.
Not hopeless though! Trying to lose 20 lbs would probably be a good place to start - 40 would be A LOT. With your large boobs, something in the range of 125-140lbs would probably be a more accurate healthy weight for you (estimating here of course).
The more you can exercise the better, definitely. Keep weight training regularly and as much cardio as your schedule will allow since you're trying to lose quickly. Try to cut back as much as you can on candy, sweets etc. and also on any proccessed carbs - i.e. white bread etc. I'm not sure how you are with whole grains and such (i.e. oatmeal) but the more of those you can eat the better, also potatoes and sweet potatoes are a good substitute. Try to have a portion of protein at every meal (5-6 meals a day) to fill you up and also fill yourself up with as much veggies as you can tolerate. Try to stick to a strict diet regime for one week eating the same amount you are now (in calories) but with healthy, good for you food and at good regular times - and push yourself to exercise. Just for a week. If you don't see ANY weight loss at all, or if you see weight gain (make sure to weigh yourself at the same time), then you should probably try dropping your calories by around 200.
Give yourself something like a 1 or 2 week committment - I find that's easier to stick to. This week, I WILL go to the gym and eat right etc.
Let me know if there's anything else I can do to help, and I hope this isn't coming accross as unsolicited advice or anything Hugs!