Of course anytime
It seems like it might be around Tier D in non-art Competitions (not Tier C because that's an individual award at the national level). Keep in mind that awards before high school don't really "count," though the 8th grade platinum is worth mentioning because you were 1st nationally (you'd probably list these all together anyways, so it would be okay to mention the 8th grade medal).
Definitely mention these since they're related to your major, and congrats on the awards!
To keep this community safe and supportive:
Rule of thumb is if you have a high ranking nationally in anything it is impressive. In your particular case, it is worth mentioning in your transcript if you are applying under IR/Polysci. Showcase as much of yourself as you can on college apps because you never know exactly what might stick. This particular award is worth mentioning and while it won't make/break an application alone, it has a wow factor that might just be the push colleges need to accept you. Hope this helps.