This is something I fear I will have to face soon...Only been playing for 2 weeks ago and just reached lvl 10 yesterday. I've watched League matches and stuff since S1, but never really played due to fear of the community.
My friend had me try LOL out once back in 2010ish, and had me play Alistar (first mistake). Went into a normal game duo (second mistake), and got flamed like crazy cause I was learning on the fly (third mistake). People were not nice at all. Basically scared me away from the game for 4-5 years until I finally tried it again this Feb cause my bf wanted me to play. This time, through proper coaching and no lack of bot games (though I have played normals with low lvl friends too), I'm getting the hang of the game pretty well, and have found champions that work well with my play style.
Everyone learns differently, and telling everyone to just toughen up is not really a good answer. Some people can grit their teeth and go through lvl30 games as a lvl20 and learn lots. Other people will shut down and not learn anything. I personally hate failure. I'm fairly competitive, but am more afraid of criticism from my own teammates. Playing in a lvl30 game where I get roflstomped would be incredibly counterproductive for me. I like to prepare and practice my skills with bots and then test them out against people my own level (or maybe a BIT higher). Growing with others around the same skill cap is a much more pleasurable learning experience.
For OP, I can only imagine what it's like to be lvl 16 and have to face lvl 30s. They have more masteries, more runes, higher skill level, larger champion pool. It sounds incredibly unproductive to fight against someone with such a huge advantage.
TL;DR Jumping into a game with higher level people scared me away from League for 4-5 years Everyone learns using different methods. Not everyone can just "toughen up" and take the ridiculous roflstomp Lvl30s have significantly more advantage over OP's lvl16 with more runes, masteries, champion pool, and skill level (probably).