Give up sugar and salt - read every food label to check how much of each ingredient there is. There is A LOT of added 'hidden' sugar in foods.
Every morning after your shower, do 30 press-ups without a break. When you've got your breath back, do 50 sit-ups without a break. Both just on the bedroom floor.
Go jogging twice a week, 3-5km each time, just gentle jogging. No need for a gym, just jog in the woods, along the river, even along the pavements. After a month or so, jog 5km and 10km per week.
When you are down to the correct weight, you only need to jog 5-10km once a week.
All the above and two fast days, (see Michael Mosley's book), per week is what I do, and am 72kg and about your height and age, with good fitness. I find it easier to do my press-ups on my fists instead of my palms, and I do those and the sit-ups every week-day, and my weekly run any day I feel like it; first thing in the morning before it gets too warm.
As well as good exercise, jogging is very easy and a great stress and anxiety buster. It gives you time to yourself, and to think etc.
Good luck !