For me, the most important thing is to mix it up. I'm in a strength class at a gym that has a lot of people ranging from 35 to 75. All the exercises can be adapted based on your condition - so as you get stronger, you add more heavier weights. A lot of women don't realize how important weight training is to ward off osteoporosis. And muscle burns more calories! So we are all able to do the same things, with new people using 4 pound weights and stronger ones using 7 or 9 (and up) weights. We work all the muscle groups in each class, but the equipment varies so things don't get boring - small medicine balls, large stability balls, barbells, resistance bands, hand weights, etc. We're very supportive of each other and the class even has 2 unofficial "social directors" to welcome new people, help them set up equipment, etc. We give people a call if they don't show up for a while, just to encourage them. (We also have pot luck dinners now and then to lift a fork and a wine glass instead of just a weight!)
The other piece is cardio - for me, a treadmill works great because I put a book on the book rack (I have a clip that holds the pages open) and I focus on that instead of the timer! It lets me read without guilt (because I'm doing "something" rather than "nothing" - as we all torture ourselves for taking time to do something pleasurable!). And my phone is in the locker room and no one bothers me or interrupts me! I set it for a target heart rate, but others set it for time or speed or distance. Most gyms provide free instruction on equipment although of course they offer personal training as well. Some people really like working with a trainer because they really have to be accountable to someone else.
A lot of women diet incorrectly and really wind up restricting their food intake so much that their metabolism slows down because the body thinks it's starving and it stores fat. So be sure you eat plenty of healthy fats (nuts, olive oil, fish, avocado) and plenty of protein. If we just eat lettuce and celery, we are nutrient deprived. I also use a balanced supplement to bridge the gap between what's in my food (which is nutrient deficient in the US, no matter what you do) and what my body needs to flourish. I have more energy than women 20 years younger, and I'm the only one in my exercise class who is never ever injured or sore - including the instructor. Staying injury-free is the key to consistent activity.
See if you can find a friend, either on your own or through a gym, who will be your partner in this.