I do not want to bulk up at this age. Weight lifting won't necessarily bulk you up. Oversimplifying this, but much of bulking up entails caloric surplus & usually lifting heavier weights with lower reps. I'd like to add, there's nothing wrong with adding muscle at your age. Here's why. Another reason.

Should I stick to 2 days of Weightlifting and rest cardio? I'm 41, 5'5" tall & currently weigh 150lbs my target weight. When I started going to the gym regularly 5 years ago, I weighed in at 200. During my weight loss phase, I worked out 5-6 days/week; ran 5k & lifted weights right after. I put myself at ~1800-2000 cal/day. This routine allowed me to lose 70lbs in a year.

Also, should I focus on legs one day and upper body other? This isn't a bad idea as it will allow muscle groups to recover.

Is it okay to exercise the whole body at the same time? Yes, it's actually one of the best ways to burn fat. Using more muscles burns more calories. That said, give yourself enough time to recover.

Is there anything that does both at the same time? Yes. One exercise that I'm fond of is the clean & press. Although it's primarily a shoulder exercise, it will also engage your Abdominals, Calves, Glutes, Hamstrings, Lower Back, Middle Back, Quadriceps, Shoulders, Traps & Triceps. An added bonus to clean/press is using lighter weights & higher reps will give you a great cardio work out! Circuit training is another way and as you progress, barbell complex is another great way to mix cardio in with weight training.

Hope that helps.