You'll need to up your cardiovascular up by a considerable amount if you want to lose weight and have your abs visible. Morning cardio is the best because you kick start your metabolism and get it running for the rest of the day. Since you've waited so long to get into shape, you'll need to take drastic measures to make up for it. I suggest that you do a 5 KM morning run every weekday morning. This will take you 20-30 minutes so you better set your alarm a little bit earlier.
This is going to be an important part to your plan as you'll want to set the right tempo to trim and tone your body into shape through a variety of high intensity exercises. Keep in mind that you want to get your heart rate pumping and keep in pumping, this means you'll need to cut back on the rest times in between sets. 30-45 seconds is all that you'll need for rest on single exercises. For superset set or tri-set exercises you'll need 60-90 seconds rest before hitting it again. Below is a sample lower body workout that you can do that will get you going in the right direction in terms of workload and tempo. Keep in mind that you should be hitting the gym at least 4 days a week for weight training at this point.
Lower Body Workout
Warmup: 10 Minutes cardio machine of choice
Leg Extension 3 X 10 Reps
Leg Curls 3 x 10 Reps
Walking Lunges Full length of the Gym and Back (Dumbbells in hand) 3 Sets
Squat x 10 plus Deadlift x 10 3 Sets Total
Pulse Split Legged Squat x 10 with Wall Squat (45-60 Seconds) 3 Sets
Leg Press x 20 with Leg Press Calf Raises x 10 (Same Weight) 3 Sets
Single Leg Standing Body Weight Calf Raises 3 x 15 back to back no rest