Well, Tracy, I hope you bet something big because you are correct! Regardless of the time you enter any of the theme parks, you must use one day of your park ticket. There are some days when the parks can be open past midnight with Extra Magic Hours, so you can get in quite a bit of magic even if entering after 4pm!
One thing to look at, though. The more days of tickets you purchase, the cheaper it gets per day. For example, with a Magic Your Way base ticket, to go from a 5 day to a 6 day ticket is only an additional $3! (taxes not included, prices subject to change.) So if you think you will want to even stop in a park for an hour or 2 on your first night, it might be worth it for the few extra dollars. Click
HERE for a ticket pricing chart.
Let us know if we can settle any other bets!