Can I get fit and healthy starting at 40?

One short 10-min workout in the middle of the week and every day I was working on my technic when I did squats.  The last three days I was out for a 50-min walk every day. One day I spend four hours in preparing wood for a stove. Since then I got a back pain and sore muscles in my thighs. Hopefully this pain will be better because I want to start my planned sport program on the 6th of January.  For breakfast I had a good choice the last days: yoghurt, oats, orange, walnuts, and a bit of maple syrup. It tasted delicious. Tomorrow I'm going to do my groceries. The meals for next week are planned.

Well, I am forty. In my youth I was used to be hyper sporty but then after some knee surgerys I stopped doing sports apart from walks. Now, I like to change that with the year of 2025. My plan is training endurance and strength with home workouts twice a week and going swimming twice a week. Exactly, Monday and Wednesday home workout, Friday swimming course because I want to learn freestyle swimming and Saturday swimming with a good friend. The days in between I want to go for a walk. Since I am working full-time and my day starts early, I want to absolve my sport program under the week after my work every day. The next challenge is to eat healthier and cook more for myself - I want to try some sort of meal-prep. I plan to cook every second evening and eat two followings evenings the same. At lunch I want to use the salad bar at the mensa at work. For breakfast I will prepare mostly a nice oats meal the evening before, because I like oats. So, how does the journey start? Aching back, a...