Take it from someone who actually plays ranked and not someone who plays more co-op VS a.i. than they do anything else. cough^ not naming names
As soon as you have played 10 ish games with a champion, at your summoner level jump straigh t into pvp. yes there will be smurfs. yes sometimes oyu will play against higher level people.
But for the most part people at your level are at the same disadvantages you are. Don't own many champions, and have no runes.
You can't buy tier 3 runes until level 20. So don't wait that long.
It is a HUGE advantage to learning a champion without runes. I'll explain
If you get good at a champion without r unes, only with base stats. and i mean good enough youd call yourself skilled.
How do you think youll play when you start with an extra 15 attack damage level 1, and armor?
The answer is, if you can last hit with low ad, can not die much with low armor, then you've already became better than the vast majority of bronze players.
It's mean to say but it's the truth.
You wanna play adc, I play adc, i know low level adc.
http://www.lolskill.net/summoner/NA/optikz/champions
thats my ranked stats this season. I'm silver 5, with 480 ranked games.
here is why i recommend learning adc in pvp before getting runes.
adc's start with 50-60 attack damage base(ish), level 1. this makes it alot harder to last hit minions whenever your attack barely does more damage then there's does.
Last hit = gold.
If you can last hit well with 55 attack damage, what do you thinks gonna happen when you start out with 70 attack damage?
You'll last hit even better because it will be easier.
There you already have a huge advantage over someone who waited until they got runes to actually pvp.
CSing against bots ( creep killing) is nothing like csing against a human player who is trying to kill you every chance they get.
So button up your boots, load your rifel ( or quiver ) and set forth ontot he Summoenrs rift for some player vs player action.
This is the only true way to get better. Experience, experience against other players.