Hitting Level 30 Doesn't Mean You Should Immediately Hop Into Ranked.

Title says it all, but if you're new to League of Legends and play the game for fun and are not yet as experienced as some other players, stick with normal games. Those who grind ranked are mostly playing to reach new ranks and climb. You will likely get paired against enemies who have loads more experience than you do, or against people who just been stuck in said elo for a long time and are still trying to get out. Just think about it before you head into ranked.

• What if I match against people who are better than me and know more?
• Should I be playing ranked with not much experience?
• What if my main champion is banned?

You'll be much much more beneficial to the teams you're on in the future if you spend your time learning more in normal games. Heading into a ranked game blind not knowing much about the game puts you and your team at a massive disadvantage. You do bad in your lane, you're whole team will pay for it and summoners rift just turns into one huge blood bath for your team. If for some reason you really want to head into ranked right after you hit 30, Which I do not recommend, then try not to play too big of a role that is key to your team. Going mid or jungle without really being seasoned in those departments will put your team at again, a disadvantage. You can cost your team the whole game whether that be feeding the enemy laner or not targeting objectives.

Don't be that guy. Play some normal games, get really good, expand your champion pool, practice last hitting, just become an all around monster and gain all types of knowledge you can. Then once you feel like you're skilled. ready, and feel like you've learned a hefty amount of knowledge of the MOBA known as League of Legends, then queue up for ranked, and make your team proud.

TL;DR: Don't play ranked if you're a fresh 30, get better at the game, then go ahead.