If you must have a hair transplant to lower the hairline, pursue a hairline specialist who has produced consistently natural-looking hairline results. You may need two surgeries to be happy. Measure your current hairline and the density that exists. Get more than two consultations for good measure. Find out why there are still many hairline repair cases being performed by the small group of hairline specialists.
Your hairline is maturing, but you do need to manage your resources as if you will recede to a class 3v. Whether you become aware of any hair loss is a probability based on time. Try to delay having the procedure by educating yourself and becoming more aware of the permanent effects that are associated with hair transplant surgery.
Firstly, you need to consider what hairstyles you would prefer if indeed you do achieve the primary goal of building a new hairline. Secondly, consider how you will heal after a surgical procedure and whether or not the possibility of unnoticeable scarring is consistent with the goal of going undetected as a hair transplant patient. Lastly, search and research what density is appropriate, and ascertain which method best accommodates your individual preferences, but also compare your case to those involving hair characteristics most similar to your hair characteristics and forehead shape.