Greetings, Marissa!
I'm so happy you came to the Disney Parks Moms Panel with your question. Your little one will have such a memorable birthday celebration at the Happiest Place on Earth!
We took our son on a few Disneyland Resort vacations around his first birthday, so I definitely understand your concerns. One of my biggest pieces of advice when traveling with infants and toddlers is to arrive early in the morning. This is when babies tend to be the happiest, lines are the shortest, and temperatures are the coolest. At park opening we head to all of the attractions that are best-suited for little ones like those in Fantasyland of Disneyland Park or Monsters, Inc. Mike & Sulley to the Rescue! in Disney California Adventure Park to name a few. I'm happy to inform you that you can take your daughter on any attraction without a height requirement, which is actually quite a lot of attractions!
When waiting in lines, you may want to use a body carrier if this is something that's comfortable for you. It can alleviate back pain when carrying your child. I also made sure to have plenty of snacks and water on hand in case my son gets hungry or thirsty. I recommend stopping by the convenient Baby Care Centers located in each park if you need a private place to feed or change your daughter. These centers also have a supply of infant essentials in case you forget anything.
If you want to experience more thrilling attractions with height requirements for yourself, you can make use of the fantastic
Rider Switch Service. This allows you and another adult to take turns watching your child while the other adult rides. This means you won't have to wait in line with your daughter for these attractions that you want to experience. It's a lifesaver!
I hope this helps, and please return if you have any other questions. Have a Zip-a-Dee-Doo-Dah day!
-Jennifer