No, your credit card will only be charged after the host has confirmed your reservation.
When you send a reservation request to a host and enter your credit card details, your bank holds this booking amount from your account until the booking has been accepted by the host. This is called authorization.
The authorization will become an actual charge only if the reservation is approved. The funds are deducted from your payment account at this time. If the host refuses the booking, or if it expires, the authorization from your bank gets canceled and the funds will be released back into your account.