I disagree, anyone can start pe no matter what the diet they consume and if you know dld's history than you will know what I mean here.
BKF, think small goals firstly and not your longterm goal. For example I'm at 8 inches now and want 9 inches but my next goal is 8.1 and than I will go to 8.2, 8.3 etc.
This is easier to keep the mind in focus and not going to destroy motivation at aiming for high numbers, which can take time than small baby steps.
Whats your routine? if its linked here than post the link, if not than make one please and I will offer some advice to help.
I've known guys on here who've been at under 6 inches length and now they are over 8 inches length, so you can do it.
If your not already, stretch your penile ligaments very intensely indeed and than target the inner tunica.
Post the routine and I will explain more.