I’m just starting out, and, honestly, I’m doing this entirely for myself at this point in my life. I’m 23 and single, and I’m really just out to empower myself and gain confidence, both sexually and in general. Look up the word “cocksure” and it says “of uncertain origin,” but I think we all know where it comes from.
As some folks suggested earlier, I don’t think most girls put an inordinate amount of stock in dick size, but if it makes you feel good enough about yourself to pursue a beautiful girl and make her life great, then it’s a win-win. In that sense, you’re doing it for both you and the Future Her.