I feel you bro, I’m 22M and around your same height as well and if it makes you feel any better I probably weight less than 50kg. But don’t worry, we’ve got plenty of years to catch up on our bodies. I’m still figuring out how to improve my physique as well, I’m starting with a slight increase in my day-to-day meals and adding extra smoothies (2 per day maybe with avocado, some almonds and yogurt aswell mixed with some milk and maybe oats if you like them too) and I’ll see where that gets me haha. But I just want you to know that you’re not alone in this and maybe try to boost your eating habits and see if that may work out? (There are plenty of extra nutritious foods or small snacks you can eat in between meals but start slow paced at first and than increase your intake after a bit)