If you can only visit one state and are limited on time I would say go to California first. Especially if you like the outdoors or want to take nature photos. As a lifelong resident of California I'm biased to the state but its not without good reasons! Here is some beautiful coast that you can see driving down south of Highway 1.
Big Sur.
Image source
https://pixabay.com/en/big-sur-california-pacific-coast-1087144/
Golden Gate Bridge
Image source
https://pixabay.com/en/san-francisco-golden-gate-bridge-3394456/
Lake Tahoe
image source
https://pixabay.com/en/sunset-waters-dawn-sky-twilight-3244610/