It's always scary when you hear irregular and then you also see the word equal. Confusing, right? Doctors need to do a good job of explaining results. I believe this just means that both breasts are dense but not completely symmetrical. This would probably be the case for most of us. But if it is a huge difference between one breast verses the other, that is more concerning. This is a small (ish) difference. Please let us know what your doctor said about it. https://www.medicalnewstoday.com/articles/321823
What does your doctor say about this? I think it is better to consult with your doctor if you're concerned about irregular density. Masses with irregular shapes and indistinct margins have a higher likelihood of malignancy( Malignant means that the tumor is made of cancer cells). But I hope that it will not be that serious and you're doing well now.
Best wishes!