Hi there, Lori!
You are welcome to check in to your hotel at any time on your day of arrival, but your room will likely not be ready until 3:00 PM, which is the "official" check-in time at the family of Disney Resorts.
If you check in prior to 3:00 PM, you can leave your bags with bell service and head out to enjoy your day. The Cast Member who checks you in will be able to provide you with Park tickets, but you will need to return to the check-in desk to have your Key to the World assigned to a particular room.
If you check in prior to 3:00 PM, you will be able to use all of the Resort hotel amenities, including the swimming pools -- so if weather permits, have your swimming gear ready to go.
And consider giving
online check-in a try to shave some time off the process.
Have a wonderful time!
See you later, celebrator,
-Deborah B.