Season 6 Placment Not Right

Was playing a game, and we are pretty even in kills at around 35min. the enemy team is on there baron side jungle walking towards baron pit, and i chat to my team "lets backdoor there inhibs while they baron" (they have 2 open inhibs and we have 2 open inhibs) and they all agree and start rushing down mid lane, and as soon as they hit the minion wave, the other team just all turned from there jungle,rushed towards mid lane and killed them all. like seriously got put in game with a bunch of bronze players fkn BS.