The problem with this approach is the scar. Personally, I'd suggest hair transplantation (FUE) to change your hairline.
Choosing to do the procedure is always YOUR decision. Of course, you need to understand the risks and what a reasonable result would offer. Patients that I have done with foreheads like yours typically find that just by hiding the most severe part of the beginning of the curve at the upper forehead make a notable "visual" difference. Be sure your surgeon has the experience to perform the excision in a manner that will allow hairs to grow in front of and through your hairline scar to better hide it. In my experience these scars almost always uniformly do great.
The position and shape of your hairline can be adjusted with a brow lift. To lower your hairline and to round your hairline would require precise excisions consult with a board certified surgeon who has expertise in these procedures.
If you have the proper scalp laxity and no ongoing hair loss, a hairline lowering operation would work for you. Also a more oval hairline could be acheived by amputating the widows peak with the initial incision.