Hi and thank you for your question! Dark circles under the eyes is pretty common and all ages and I commonly treatment patients in their 20s for this condition. There really is no harm in starting fillers early on as long as you are doing it with a physician who is highly experienced in these procedures. With regard to benefits, you will mostly likely enjoy a rejuvenated and more refreshed look in the years to come as you are replenishing the volume. I have seen patients who have postponed taking care of their volume loss for 20-30 years and by the time they come to see me, it might be too late or they might need several syringes of filler to see good improvements. I have also seen patients who don't do much on the face for years, thinking that when it gets "really bad" they just go and fix everything by a facelift, which is almost never the case because a face lift can't do much with the volume loss which is the real problem here. As long as you work with an experienced physician who focuses on natural looking results, you should be fine. I hope it helps and good luck!
IMPORTANT: These answers are for educational purposes only and should not be relied upon as a substitute for medical advice you may receive from your physician. If you have a medical emergency, please call 911. These answers do not constitute or initiate a patient/doctor relationship.