Hi there, Citlali!
Welcome to planDisney! Thanks so much for coming to us with your question. I've visited the Parks both with and without purchasing Genie+ and I will say that, if experiencing attractions is the primary focus of your visit, it is totally worth it and will save you tons of time from waiting in standby queues.
Genie+ may be purchased either as an add-on at the time of ticket purchase or after scanning your ticket for admission on the day of your visit. If you do not purchase Genie+ initially, you are unable to do so until you scan your ticket. Also, if you purchased a multi-day ticket, you may add Genie+ to your entire ticket duration. If you purchase on the day of your visit, you may only purchase for that specific day.
Please note that, unlike Walt Disney World, you are unable to make your first
Lightning Lane reservation until you have scanned your ticket and entered the Park. Genie+ is sold on a limited supply basis, so there is a possibility that you might be unable to purchase on the day of, but that is a rare occurrence. Functionally, there is no difference between Genie+ purchased online vs inside the Parks. For a multi-day ticket, you will have to purchase Genie+ each day you enter the Parks.
There's so much to look forward to at the Disneyland Resort this year! I just returned from the kickoff of the
Disney100 Celebration and it was fantastic!
Mickey & Minnie's Runaway Railway has become one of my favorite attractions and I cannot wait to take my kids on it. Remember to take advantage of Disney
PhotoPass photographers since they are included with the purchase of Genie+. And do not miss
Wondrous Journeys, the new nighttime spectacular!
I hope this information was helpful for you, Citlali. Please do not hesitate to visit us again here at planDisney if you have any further inquiries. We're here to help!
Have a Magical Day!
-Al