Is weighing 54 kilograms at 170 centimetres underweight? Or for you Americans, is weighing 119 pounds at 5 ft 7 underweight.
I just posted in the good news thread about this - I’ve been working to get into shape and just hit 120lbs at 5’7" as well. From everything I’ve looked into (and I’ve done a lot of research in the last year), that’s not underweight. It’s on the low end, but you’re fine. 115 or under is when I’d start to be concerned.