Hi there,
Dermoid cysts are the most common ovarian tumor and extremely common at your age. because a dermoid cyst contains alot of fat, it can be easily identified and diagnosed by ultrasound. Pain from a cyst can occur because it is twisting ('torsion') or because due to a large size, the cyst presses on surrounding structures. Otherwise, ovarian cysts can be quite large and not cause any pain or other problems. (The abdomen is a roomy place.)
For you, one of the questions should be: why do you have pain? If you have pain for another reason (such as round ligament pain which will improve as the pregnancy continues, or a bladder infection, or a bowel problem), then it is reasonable to leave the cyst alone.
On the otehr hand, if the pain is clearly from this ovarian cyst and it is not getting better, that is a reason to remove it.
In general we like to wait until the second trimester of pregnancy ( more than 12 weeks) to do surgery in pregnancy. All the major organs are forming in the first 12 weeks. While anesthesia is probably safe in pregnancy, we do not like to expose the fetus to any additional chemical when possible. Also the highest risk period for miscarriage is the first 12 weeks.
You should go back and explore these issues with your doctor.
take care