Ranking - Season 6

So while I was at Pax South, I had a discussion with a few people who all told me that no matter WHAT I do, I will be placed in Bronze 5 when I get my Rank, even if I win all 10 Provisional Games. I believed them because my boyfriend and his friend were placed in Bronze 5, but they were Silver in Season 4.

So I told this one guy in particular (who is Platinum) that I attempted to get my Rank the week before Season 6 I had won 5 out of 6 games, and received 2 S ratings, 2 A ratings and 2 B ratings. He said, your Rating doesn't matter, it just gives you more EXP on your Mastery Level for that Champion if you do well.

So WHY is that? If he is correct, that makes NO sense... Like, if i Solo/Duo Queue in a Ranked PUG and we LOSE, but I "score" an "A" at the end of the match... I will be penalized based off the performance of the other 4 people? Additionally, if I Solo/Duo Queue in a Ranked PUG and we WIN, but I "score" and "C-" at the end of the match.... I get rewarded for MY bad game because the rest of the team did well?

Is this correct? Because it seems like a win/lose for your PUG team SHOULDN'T determine YOUR PERSONAL Rank. (If however, you're in a TEAM Ranked Queue and your Team wins/loses, then the system of Win/Lose makes more sense)

Can someone enlighten me , because I've been afraid to even PLAY ranked thinking that I will (not matter what I do, even if I win all 10 games) be placed in Bronze 5.