First, there is a look back provision in California.
California specifies that a claim for refund or credit must be filed no later than (a) four years from the original due date of the return or (b) four years from the date the return is filed if the return was filed within the "automatic extension" period. Additionally, a claim for refund or credit is timely with respect to payments made within one year of the claim filing date (the "look back" provision).
Your process looks good but you would need to start with your 2014 tax return.
