A PPL shows you're keen about aviation and having acheived it at such a young age shows determination. But as for giving you an advantage in flying training, I would say it was of limited value. You will have to 'unlearn' some of your techniques and get rid of (dare I say) bad habits.
I base this on two tours as a QFI where I saw many people such as yourself. You will have a bit of an advantage over your peers at first, but after about 30 hours or so, ability will show through and you may possibly find yourself dropping behind others on your course. As an aside, I found those students with gliding experience to have a slight advantage over those with PPLs.
However, don't stop flying now you have the PPL. Stopping now will speak volumes to the selectors. Do enough to stay current, but don't expect it to give you an advantage if (sorry, when!) you start your flying training. And when you do, keep your PPL quiet. Your QFI will know you have a PPL, he will have read your file. But don't say "When I was flying the C150, we did it like this". I can guaretee it will annoy him quite quickly!
Good luck.