AoPS has much better competitive math classes and would be a much better source for clubs/other outlets for testing. I’ve been active with both for many years.
With AMC testing virtual this year, finding a location to register with might be easier. Our local club had a couple folks attend in person last year that were not members, one of which who travelled a good distance. MAA lists locations that are open to testing to anyone - usually local colleges. I’d find the nearest one and reach out to the contact.
Last year’s list is here - probably good candidates for an early start - https://www.maa.org/math-competitions/amc-8/locations