At age 68, 20 pounds overweight, I decided to start jogging to get in shape. I was already doing a leisurely one mile walk every day. I had run for exercise when I was young, but it had been decades since then. The running gave me more physical stamina, which I expected. More importantly, it gave me more mental energy, which was a big surprise.
I tried to jog the same mile that I had already been walking every day. I could only jog 50 yards, then was so out of breath that I needed to walk 100 yards to catch my breath enough to jog another 50 yards. I kept this up for the whole mile. After about a month of this jogging/walking routine I could do a very slow jog for the whole mile without any walking. After about six months I could jog a 10.4 minute mile on a good day. Quite a contrast to the seven minute miles I could do when I was young. But I felt better, slept better and had more stamina. I did not loose any weight, though.
I did not get running shoes until about the third month. I should have got them first. They are especially useful on hard surfaces. After I got in shape, I burned enough energy that I needed less clothing to run. In warm weather it is essential to get up early and run at the coolest time of day. In warm weather tennis shorts and no shirt are enough. When it gets as cool as 50F/10.0C it will be comfortable with a long sleeve cotton dress shirt and no undershirt. The ideal temperature to run dressed this way is 38F/3.3C. Colder still, add gloves. Colder still, add wool cap that pulls over the ears. When the temperature is 32 degrees F, 0 degrees C, I sometimes wear cotton/polyester long sleeved shirt and pants, no undershirt, a windbreaker jacket with no insulation, a wool cap that I can pull over my ears, and leather driving gloves. It is almost too hot to run dressed this way at 32F/0C with no wind, but very approriate if there is a stiff wind. The ideal temperature to run dressed this way with no wind and the sun shining is 18F/-7.7C. The main problem with running in freezing weather is dangerously slippery surfaces. You do not want to risk a fall by running across a patch of ice. If you come to a patch of ice, quit jogging and carefully walk across it.
A word of caution from long ago. Getting in shape should be a gradual process, and should not be rushed. When I was young I got out of shape and was determined to get back in shape as quickly as possible. I really pushed myself, and my knees loosened up enough that they could bend backward a little bit. Then I climbed a tree and sustained a permanent knee injury that I have to this day. I can jog forever, but a sprint will still hurt my knee. Do not push yourself too hard, and if your knees loosen up you have overdone it. Do not do any climbing or kneeling or put any avoidable stress on loose knees.