Hey man, if you feel like diving into ranked but get anxious, there is a lot you can do to help yourself over it.
I have ranked anxiety (unfortunately related to my problems irl) but I've managed to work on it and play around 200 so far this season. At the start of the season I'd get very agitated in queue and champ select, short of breath and shit, it was annoying as fuck. Now it feels like i belong playing ranked and have slowly climbed to plat. Instead of worrying about what can go wrong, accept you can have a troll/flamer, and realise you are in control of your own performance regardless and try to learn.
The best way imo to work at these things are to start small and ease into ranked. I used to take a duo friend on Skype to help me at first. If you have someone you get on with this is a good start. You want to eventually be able to queue up on your own though, so after a week or so try just one or two on your own.
Other things kinda work like tricking yourself into queuing up. Sounds mad, i know, but i would do things like "oh ill just queue up as my roles, then remove it if i feel uncomfortable", then a min into queue I'd just be like, "ahh might as well see what champ select looks like" and so on until I've tricked myself in to a game. Then the second game of the day im just no messing put myself in queue. After 4 months of ranked i dont even think about it anymore.
As for nervs in game, this is quite normal too. You want to forget about losing lp, having people judge your rank ect, and just focus on doing what you think is right.
Other tips that helped me included playing without name plates on, mute moaning people the first time and dont waste time on them, and to get that even in ranked its just a game. At the end of the day, i dont want to let my team down, but its not exactly life or death. Get that pressure off yourself and have some fun!
Good luck