Are you ready for Ranked? You don't know, and that's OK. Some people will say yes, some people will say no. That's all speculation since we really don't know you as well as you know yourself.
Point being, play some Ranked to give yourself some perspective. Maybe it'll take a few games, maybe several.
The most important thing to keep in mind is the distinction between Normal and Ranked, that being YOUR OWN PERFORMANCE IS NOT HIDDEN FROM YOURSELF OR OTHERS. It's all out there, the good, the bad, and (most importantly) the ugly. And it all follows you throughout the season. Manage your exceptions accordingly.
I really have to place emphasis that "all stats follow you, good or bad" because this is where a lot of people lose it and why they shy away from Ranked or get bitter about it. You have to understand that for every LP (or more accurately MMR) lost, you will at some point have to regain in order to progress forward. For every death suffered, you will need to make up for with a kill/assist to raise your K/D/R.
That being said, don't dig a hole for yourself. If you lose 20 games, you will have to generally win 20 games to JUST BACK BACK TO WHERE YOU WERE (you didn't actually move forward). So how do you know if your ready? Simply put, you are winning more than you are losing. If that's not the case, then you are not ready. Switch back to Normal and practice there, don't accrue loses in Ranked that you will have to win back later. Just win in the first place. Sounds simple, but so many people overlook this.
There's a lot of concepts, mechanics, and strategies too. People can talk their heads off, but in actuality there is too much to talk about. So don't worry about it, go into a game with what you know. You will know what you need to work on because... YOU WILL LOSE A GAME TO SOMEBODY THAT DID IT BETTER. That's OK, that's literally how everyone loses. Take note of it, practice what you need to work on in Normal, then take what you learned to Ranked and beat other people with it. Surprise someone do something better then you again? That's fine, repeat the process. You will get better, and eventually not many things will beat you anymore. If something does, that's great cause it's something you can assimilate and use against other players (and they can't use against you). This is the Ranked mentality, this is how you become the best.