Pro Tip: Don't play Ranked (reasons inside)
Here's the "catch". There's not enough people on the leader to give your ranking an accurate placement if you play at the start of the >year.
Like seriously http://euw.op.gg/statistics/tier/
EuW population last year around September was ~2.5 or so million players. Right now it sits at 45.000 players in total. Your rank shows as a comparison with those other 45.000 players. Now with the 2.5 million in the past year.
This is the "disadvantage" of playing ranked in the first month. You will drop tiers, you will most likely get >bronze or silver unless you are REALLY good. Because the system doesn't have who to compare your performance with.
Last year, Plat 4 at 0lp (which I had) was in the best 200.000 players on the server. There's not even that many >players right now that it was last year from plat 4 to challenger.
Edit: just checked Korean server. They got 50% of their population in bronze atm (140.000 players total). While we only got 33% in bronze on euw. But on the good side, they got 3 players in dia 3 and 1 player in dia 4. We only got players in dia5
Like really, its just new ranked year symptoms. Wait for 1-3 months and you could easily get your last year placement.
In short: if you play ranked now, majority of the community isn't ranked, so you will be classified only on those who ARE ranked, they are very few and out of them all, you'll most likely drop tiers unless you go 10-0. (even going 9-1 made few players I know drop 3-4 divisions)