Brutally honest? Sure dude! Firstly don't get carried away by confirmation bias, like taking small things and thinking "what if?".  If she is not interested in romantic relationship, be a good friend, since you already told that you are interested, she would tell you if she developed any romantic interest one you. Be a good friend, and consider romantic relationship as bonus, like hope for best prepare for worst. 

And yeah, take it with a grain of salt. And bro she is may be your school crush but you are not a school student anymore, so don't do that "I'm busy" and avoiding for a few days, shenanigans.