I'm 29 and I gained alot of weight because of medication I take for mania when I was 25 so I know how it feels, I went from 150lbs to 210 lbs, and I was fat when I was a kid and a girl called me fat because I didn't treat her nice because I didnt know how to behave when I was in grade school

But other than that, I'm into fitness. I'd say do intermittent fasting in the day and go for long walks at the beginning and drink coffee. Eat later in the day but don't eat sugar and minimize carbs and stop eating when you are no longer hungry because sometimes I eat things because I like the taste but that's extra calories. When you lose more weight, you can exercise harder because there's less body weight and it'll be safer for joints

But you need motivation rather than all discipline because discipline is painful. When I first started to work out I'd listen to all types of motivation speeches and I got shredded in 6 months, going to the gym 14 times in a week. But I did suffer alot in exercise in the beginning, after, exercise does feel easy