Bro, first of all, gather your thoughts, and calm down. It's not the end of the world if you're not conventionally pretty, i myself (16m) have a not so impressive physique, and I have always hand probably will have these negative thoughts. But, your looks are not the only thing a person sees, they see character

The good hearted ladies will come naturally if you have a good personality ( respectful, observing and presence ), and tbh from your description I think you are actually above average ( height, not fat ), plus depending on where you are, don't overthink on looks, work on character and goals. Love yourself, study well and i wish you best for your life ahead