If you're worried about growth plates you shouldn't be running Ostarine. Pick up ArA and wait until you're done brewing m growing before messing with your hormones
This x100. Wait until you've tapped out naturally before messing with SARMs or PHs. If you're young enough that your growth plates aren't closed then you should be taking advantage of your natural hormone levels. Train hard and eat harder and you'll grow. ArA is a nice natural addition, but stay away from the others for awhile. It's dangerous to young guys because yeah, you might see great results on a SARM or PH, but if you f*ck up your PCT, you can ruin your natural test levels. Believe me, from someone who is on TRT at the age of 31, you don't want to be on TRT the rest of your life!
Definitely take advantage of AM though because you'll gain a ton of great info on training, nutrition and supplements (when the time is right).
Good luck bro!