Those numbers might not be what you’re expecting, but that doesn’t mean they are incorrect. Your New queue isn’t necessarily numbered from 0 to the most recent card you added. It’s numbered by adding 1 to the highest number that has been registered in the New queue – which includes any decks/cards you’ve imported, and the New-queue numbers that they came with, even if you later deleted them.
As long as the cards are in the order you want them, it doesn’t matter if they have consecutive queue number, or what numbers they are. So, there’s no need to do anything to “fix” this now [unless they get into the millions/billions, because then they can get unwieldy, and might be worth fixing] – but you can adjust them back down if you want to.