First off, I think you've got an admirable attitude and a noble goal. First things first, focus on getting to a GOOD BASELINE.
Build up your cardio, little by little, but not by going longer, go HARDER. Do 20 minutes a day, first walking, then walking and jogging, untill you're up to a 2:1 ratio of work/running HARD to walking.
Also, definitely make sure you're getting mobile. Get a foam roller. Stretch. Learn to "Third World Squat". You've definitely got things in your muscular system bound up at your age and activity level, and it needs to be free.
I'd also work on pushup progression, just do as many as you can, going from knees if you have to, until you can do 50.
Same thing with bodyweight squats, do them from your heels and very deep. This seems like a easy waste of time, but it's not. Anyone in this forum, do 200 bodyweight squats, deep, in as little time as you can, until your legs are on fire, then tell me it won't do ****.
After a while of this watching your diet and improving mobility and BASIC strength (squat and pushups force you to stiffen your core, so you get functionally stronger), you'll be ready for a real gym program with weights and stuff. OR a hoem workout tape like P90x, really whatever agrees best with you.
Just remember a few things:
Diet is 85% of fat loss.
Exercises that use the BIG muscles are effective. That's back (pullups or inverted rows are easier at your weight), chest (pushups) and legs (squats). Do them with good form and with full range of motion. Don't worry about your ego.
CONSISTENCY. You can do it. It will take time. This is a LIFESTYLE change. You're getting healthy.
Also, I have a bunch of programs and my diet guide at ogrestrength.com
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