Dermoids are not like other types of cysts. They are mostly solid and cannot go away on their own. If you go to Google Images and do a search for dermoid ovarian cyst, you may be a bit shocked at how ghastly looking they can be. So I don't think rupture is likely. The greater risk would be twisting/tortion of the ovary tube, which could lead to emergency surgery. Or they may grow further, or just stay the same, and not cause much more trouble than you already have. But they will haunt you one way or the other and you may want surgery at some future date and time. That larger one might interfere with the ovary's ability to function/release eggs. Or it might not. Might complicate a pregnancy, too. Or not. Sorry for the good news/bad news, but that's how unpredictable life with a cyst problem can be. They reduce quality of life, and it varies by person just how much.
I just wanted to add to my comments, after reading further into older posts by others. Dermoids can rupture and if they do, they disperse their solid elements into your abdomen. That can be teeth, hair and other solid components. It could lead to a nasty surgical clean up. I am not trying to scare you. Just want you to have more things to consider when making a decision to pursue or delay any surgical options.