Hello Jessica! It is always very exciting to plan a vacation to The Most Magical Place on Earth. You're asking a great question. Knowing which tickets to purchase is always a good start to your planning!
Tickets to the Disney Parks come with expiration dates. When you purchase tickets, you choose your start date and the number of days that you want on the ticket. Your selection sets the dates for which the tickets must be used. Once selected, the ticket cannot be used for admission before the start date or after the "valid through" date. It sounds to me like you've selected a time frame for ticket use which will have your tickets usable through July 5, 2021.
Jessica, if you have already purchased tickets for the Disney Parks, but find that you need to make a change, you can usually make changes. For example, you can add days to your existing ticket or you can even upgrade your existing ticket to add the
Park Hopper or Park Hopper Plus options.
It looks like you have plenty of time to keep planning! If you find that you have any more questions, please come visit again!
Hakuna Matata! Jonathan G.