Keep playing with your level 30 friends until you reach level 30. As soon as you hit level 30 straight to ranked solo q.
You'll thank me later.
Thanks guys for all the feedback.
Bear in mind that Newt is quite possibly trolling you here. Going straight into ranked after getting to level 30 means you will very possibly place into bronze and have a bad time. Feel free to play normal draft if you want the pick/ban style, until you're comfortable with a few different champions and roles.
I mean, some people might not mind placing into bronze, but the competition there is unlikely to teach you very much.