How to handle these awkward and not so awkward situations

I had gone to a certain function had no expectation of any person who I know would come but surprisingly I found my one Classmate there ( girl ) though I had seen her from distance only but I did not or introduce or talk anything cause I do not wanna be felt as a desperate person or bowing in front of her if she had said my name or said hi I wousl have definitely talked with her but it did not happpnedd there were many incidence where I coudl talk but I did not actully she was not like whom I had talked with her in school much or anything but ig saying hello would not have created problem may be I was not ready to broke thr steal cause things coudl have been more awkward if she had did not recognized or dismmised as a stranger 💀 ,next time how can I handle or start conversation may be I was a little afraid to fail here making my mood more sad that's why I did not joined in .