Translate into english please! i'm beggin' you...

blin... mozhno skazaty "i study maths", no nel'z'a govorit' "i study in the institute" v tom smysle, chto vy imeete vvidu. i study in the institute = ia delayu uroki v zdanii instituta
aeronautical -aerokosmichesky

"I go to Institute of (Civil) Aviation. I decided not to come up to you that time because I couldn't start a conversation with a person I know so little. Besides, I wasn't sure whether you would enjoy talking to me. "

couldn't - potomu chto soglasovanie vremen

I AM STUDYING AT THE INSTITUTE IF CIVIL AVIATION..I did not come up that time because I can't start talking with a stranger...and..who knows i might be unpleasant for communication..

Лучше сказать I study, т. к. на тот момент, когда Вы говорите с собеседником, Вы не занимаетесь усиленно в институте, I mean не сидите за партой :-)
и я бы заменила Stranger на "the person I don't know well"

Лучше всего сказать: I am studying to be а (вставляешь профессию на которую ты учишься) in the aeronautical institute.

I study in the aviation institute. And at that time I did not approach because I can not begin the conversation with stranger man, besides, who knows all of a sudden I would have been unpleasant for you to communicate!

I attend Aviation University. This time i did not approach because i could not start the conversation with the person that i was not familiar with. Plus, i am not sure how the person would react when i started talking to him/her!