Welcome to the forums, @Anonymous! Do you happen to know your Experian FICO 08 score? The bar isn't too high for Amex charge cards. It's hard to know whether the mailer is just marketing or a true prequalification. You may want to check this link to see if cards come up:
https://www.americanexpress.com/us/credit-cards/check-for-offers/
Even if cards don't come up there, it doesn't mean that you wouldn't be approved. But if they do, that's a good sign.
Green, Gold/PRG, and Platinum all seem to have the same underwriting requirements. As @Anonymous said, no one can guarantee you approval, but it would be helpful if we knew your Experian FICO 08 score. You can get a free one via Discover at creditscorecard.com
With a 691, you'd have very good odds of being approved for a charge card assuming there's no recent negative information on your reports. If you waited until those paid cards reported, your odds would be even better. Completely your decision, of course, but if the card fits your spending and what you want from rewards I'd personally go for it.
