54 in the 400 definitely won’t get you recruited somewhere like CMC, although you could probably walk on. Personally my 800 dropped like 10 seconds when I actually trained so you could probably drop the 3 seconds in the 400.
If you are or probably can be in shape to run distance, I’d recommend considering branching out into cross country. It can help you get way better at mid distance stuff like 400s, and if you’re actually decent at it, it helps you diversify you as a runner, gives you credentials in a sport with a less stacked field, and legitimizes the idea to colleges that you actually care enough about track to run competitively year round.