Gem level requirements?

I have 5 lvl 20 gems in my stash. I am lvl 83. They would help my build greatly but i cannot use them. Using a lvl 20 gem requires me to be at lvl 90. These gems would help me get to lvl 90, then i assume this happens again. Why? It's like fighting an invisible wall. I have begun to reforge every map till t15 and using the OMEN OF AMELIORATION and saying hail mary just to use the gems i have earned. Why?

Cannot socketed gems just lvl up, as long as they are kept in a socket?