I thought CA had 26k cases.
We would need to grow by a factor of 20,000,000 / 2,617 = 7,642
A 2% growth rate per day would need 1.02 ^ 452 days = 7,713 in order to exceed the needed factor. So about 15 months.
If we change that to a 5% growth rate per day it becomes 1.05 ^ 184 days = 7,921. About 6 months.
I'm not saying this is going to happen, how a disease spreads is obviously more complicated than this, just a few rough examples of how relatively small growth rates still become large fairly quickly.