Im the same age and height as you and so is my best friend. She weighed 84 just over a year ago and now weighs 69. She doesnt exercise much a part from walking the dog but she eats super healthy. Its all about how much you consume and what you are consuming. I started the same healthy eating as she did and have so far lost 3kgs. My current weight is 74 and I want to be 68. For breakfast I have oats or boiled egg, lunch I have a protein and salad and dinner I have a protein and veggies. I try not to snack and if I do its nuts or fruit. I calculate my calorie intake and have a Fitbit the One to help me track everything. It may sound like a hack but if you serious about losing weight yoy need to make a lifestyle change and become "health conscious".