Let me introduce myself-- I have recently gone online and came across this site. I have shoulder length hair (have not cut it in 4 years) and plan to let it grow as long as nature will allow!
If you have not cut your hair in four years, and it is only shoulder length, I don't believe you will ever have hair longer than what you have right now. Everyone has a terminal stage where the hair stops growing. Considering that most hair grows (on average) 6 inches a year, your hair should now be (approximately) 24 inches long. That is at least mid-back length. I hope you are satisfied with shoulder length hair. ;)
OK, actually it reaches the top of my forearms. I measured it and it is over 16 inches. When in a ponytail, it is approximately 1/3 the way down the back. But one thing I do know is that I will never cut it!!! That's for sure!
Right on!
Welcome to the board, john! And best of luck in hair growing and keep us updated about your hair, with some pics (if you might).