I am 46 and proud to say that this was my 2014 resolution which I succeeded at. I was athletic in HS, and I am about as fit as I was back in my late teens. It took a while. I am 5' 10". When I started in January 2014, I was around 205-210 pounds and looked like I was in my 3rd trimester.
First, walking an hour+ per day for a few months. Backing off of breads/cheeses and creams and giving more favor to fruits and vegetables. Target diet was roughly 1,500 calories per day. The high fiber content of fruits and veggies allows you to stuff your gut without too many calories. If you fall off the wagon a few days, you don't punish yourself or feel disappointed. You accept it as a short "break" and get back on the wagon.
Then, some jogging. Then, torn muscles that had to heal (getting old made getting athletic a bit precarious). Also, calisthenics on a somewhat regular schedule off-and-on. Finally, 175 pounds, descent muscle and the beginnings of a 6-pack. My diet is not as strict as when I was losing weight. I eat pretty much what I want, including ice cream and cereal.
Among my age group, I now often find myself to be "the most 'fit' person in the room." Good luck to you! It can be done.
Congratulations, Outstanding.....