Here are some recommended exercises for older women abs:
1) Crunches along with Rotation
For the upper women abs, crunching with rotation is a good exercise. Adding rotation targets the oblique. If these exercises are performed properly they are easy. Don't add free weight or stability ball while doing these exercises as it will make things quite difficult for you. Lie back, keep your knees bent and put your hands behind ears. Relax the neck, shoulders and upper area. Push your back to the floor and breathe out. Slowly crunch up until the shoulder clear the floor. Twist towards right and twist back to center while lowering yourself to the floor slowly, as you breath in. Now crunch back upwards and this time twist towards the left side. Go back to the floor and start again with 5 reps each side with exchange. Do two sets of 12 reps.
2) Planks
Planks strengthen your upper body part and abdomen. There are some customized versions of this exercise which are less tough on wrists and shoulders. Lie back on the stomach and bring forearms under your chest together. Grip your both hands and push up so that your body rests on your toes and forearms. Don't raise your hips higher than shoulders and also don't let your body to swing backwards. Your upper body must be above your arms. Grasp your abs & gluts and hold yourself. Don't forget to breathe. Keep this position as long as you can and go up to sixty seconds.
3) Reverse Crunches
Reverse crunches relate to lower abs. While doing this exercise, lie on the back while knees are bent, keeping your feet flat on floor, arms on the sides while flatting your lower back. Now raise your knees above your hips. Just keep them bent. Now lower legs towards floor but keep your back as much flat as possible. Breath out as you lower the legs and breathe in as you raise them back up. Do this ten to twelve times and in 2 sets. If you find it difficult then lower only one leg at a time.