@Jillian115
I am experiencing a similar thing lately. @Emiel1 is right in that you never need to decide an enquiry, only respond in time, and that it's best to ask the guest to withdraw the request as they have nothing to lose.
However, you do get those frustrating ones where the guest is either unresponsive and doesn't get back to you/withdraw in time or those that simply refuse to and try to persuade you to accept the booking. That used to happen from time to time but now seems more common, plus I've lately been getting IBs for guests I would not be willing to accept, often fairly short notice ones, which means having to get on the phone to Airbnb to sort out the whole mess.
I think it's a combination of COVID and the holiday season, which is making guests 'panic book' listings even when it should be obvious those listings are not suited to their needs.
As for the acceptance rate, I have been repeatedly told by CS that it's not that relevant and hosts will only be at risk of being delisted if they have a very high rate of declined requests.
Under Basic Requirements, it shows that you should have an 88% or above acceptance rate, but I frequently fall below this and have stopped worrying about it, as it has never caused a problem and I've never been contacted by Airbnb about it. This target is just there to pressurise hosts into accepting more bookings.
Response rate is far more important as it does affect your Superhost status and is also detailed on your listings. Therefore, ask the guest to retract the request (they usually do) and if they don't, decline it close to the 24 hour deadline as you can. It's better to decline than let a request expire.