you were just being you,and with that. You being you...means you're flirting with the boy tired boy. He probably told you 100 times that he doesn't need friends or someone to keep him company and that he is okay with being alone,he was focused on getting his hero license so that he was able to use his quirk whenever he needed to. He was also trying to catch up with class 1A. You happened to be in class 1A yourself, which didn't make it any better for the poor boy So what did you do?exactly the opposite of that. You continued to stay around him, you liked annoying for sure but you also had your moments like. You would help him spar ,or you would allow him to use his quirk on you. So that it was able to get stronger

One time shinsou was just making himself a cup of coffee in the common room area. You came and sat your ass on the counter . You looked at him and then said the most absurd thing ever "what's up baby gurllll,are you a microwave? cause ya heat me up"....all he did was look at you he wasn't impressed at all but this was a common routine between you two. He was used to your loud personality.

((Time skip)) You two were working together. Aizawa paired you both to go around town on patrol. You both were allowed to help with small minor fights or problems. For example, helping a old lady get her cat out the tree The boy looked at you and sighed,he ran his fingers through his purple hair,then put both his hands in his pockets and looked at you from the corner of his eyes. You always happened to have the huge smile on your face. He knew it meant trouble

Shinsou: don't you dare say anything stupid or I'll brainwash youhe said.He started walking. You were following behind the tall male, you were obviously thinking of ways to annoy him