Hi there, Adilene!
Thanks so much for bringing your question to us here on the Disney Parks Moms Panel. Your trip to the Happiest Place on Earth is right around the corner!
Before you arrive, I recommend looking at the official Disneyland Resort
Park Rules and Regulations to see exactly what is allowed inside the theme parks. Unfortunately wagons are not permitted into the parks, but strollers are more than welcome as long as they are less than 36" wide and 52" in length. Starting May 1, 2019 stroller restrictions are changing slightly. On this date, strollers greater than 31" wide and 52" in length as well as stroller wagons will not be permitted. If you do not have a stroller, you can
rent one directly from the parks on a first-come, first-served basis each day. This is a great option for many Guests who don't want the hassle of having to bring a stroller from home. If you need some extra space to store items throughout the day, you will love the convenient
locker rentals in both parks. You can access your locker all day for one low price, so I always rent one to keep extra clothes, souvenirs, and even snacks.
If you have little ones, you'll definitely want to check out the Baby Care Centers at both Disneyland Park and Disney California Adventure Park. These offer semi-private areas to feed or change little ones. They also have cute little toilets that are perfect for potty-training toddlers.
I hope this helps, and please return if you have any other questions. Have a Fantasmic day!
-Jennifer