Any tips for insecure 18 year old.

I am a male and just turned 18. I was preparing for jee and will get a decent rank and will go to IIT. But this journey completely messed me up, I am quite skinny and have a bit of hairfall too, I am around 5'6 ( feel it's kinda short ) and I am insecure about my height because well people keep saying I am shorter compared to my father whos 5'9, I would say looks wise I am not bad but definitely not great. So any tips for me to improve myself and built confidence?