why did i ruin my relationship with my sis tho?

so last year when im like 14 and she is 18 we r getting close again after being super distant for years, but it's all chill, like watching movies and stuff. i dont know why but i just feel this weird pressure to be friends again with her after so long of not talking. one day my sis tells me something kinda private that happened at college, and i feel bad but also really curious, so the next day im on google searching up all these things i shouldnt be looking at. then i tell my sis about it like we were in cahoots or whatever, thinking she would be cool with it since she opened up to me. turns out she is super pissed and cuts off contact again. now im wondering if i was just not ready for a real friendship after being away for so long? was i just looking to be friends because i felt guilty for the past or was it about something else, like wanting her approval or attention? ive been thinking this over and trying to figure out my own feelings here.