Hey there, Jennifer!
Welcome to the Disney Parks Moms Panel, and thanks for your wonderful question. I'm glad you are preparing yourself for your vacation by reading through all of the
Park Rules for the Disneyland Resort.
You are correct that stroller guidelines for the parks have changed recently. To measure your stroller, you will want to just use a tape measure from the longest points for the length and width. Strollers must be no larger than 31" in width and 52" in length. As you approach security checkpoints at the Disneyland Resort you will notice stroller size guidelines labeled on the ground. Your stroller cannot extend past the edges of the box that is on the ground. I hope this helps!
If your stroller is too large for the parks, no worries!
Stroller rentals are available for single and double strollers right in front of Disneyland Park. Just make sure to arrive early in the morning to guarantee you will be able to rent one as they are available on a first-come first-serve basis each day. Know that stroller parking is conveniently available near all restaurants and attractions in the parks.
I hope this helps, and please return if you have any other questions. Have a magical day!
-Jennifer