Hey Lindsey!
I love that you are planning your trip already! Since you are planning in advance, you have some great options in saving to pay for the trip.
First, Disney Park tickets can be purchased in advance. Usually, Walt Disney World Park tickets increase in price each year. If you decide to purchase tickets now, you'll avoid paying any price increases which occur between now and your trip.
Another option for saving for your trip is to purchase Disney Gift cards. Many people save these gift cards over the years, and then pay for the trip using the gift cards. This lets them slowly put away money towards their trip.
About a year before the trip, you'll be able to book your room. If you already have your tickets, you can purchase a Room Only Reservation. Keep an eye out for
Special Offers and choose the time of year where crowds & prices are lower. This will help with the budget too!
Hope some of these tips help you plan!