I was in the same shoes and yeah the stretch marks and loose skin are there but it’s nowhere near as bad as being fat. You’re using that as an excuse to not change yourself.
Just start fasting. Do 24hr rolling fasts to start with. Stretch marks are scars, they are permanent damage to the skin. You may be able to minimise the appearance but they are there to stay. I have a pic in my post history, that is what I look like after losing 100lbs at 25.
Edit. You’re 23 and want to weigh 58kg at 6ft? That’s 127lbs. That’s really underweight and could make you ill. Maybe it’s tempting to go as low as possible as like a form of self punishment, I’ve been there, but you do not need to lose that much. 30lbs at the most, depending on your frame.
Do strength training while at it & tone what’s underneath.
Edit: Dude WTF 58 kgs at 6 ft 😵😵😵 at your height IF & workouts will make you a smoking hot mf in no time. Where did you even come up with the absurd idea to lose 30 kgs. That’s sick.
Just start. Once you get into a fasting groove, I would add regular 72s. Also eat clean, take collagen and some think dry brushing helps. There is only so much you can do. Some get lucky, some get surgery. The longer you wait, the harder any of it is gonna get. Work on your emotional management and relationship with food (Dr. Rob Cywes YT vids on carb addiction and vulnerability to addictive behaviors is great for this). You can’t keep going up and down, it is really hard on your skin and health. Start with your next meal and go from there.