Procedure for obtaining Spanish citizenship for adult child of Spanish Citizen by residence

Hi!

I am a Filipino citizen.
My mum has become a Spanish citizen by residence recently.
She has informed me that for me to obtain Spanish citizenship as well, I have to be unmarried and below 31 years of age.
I am now 27 years old.
How is the process? And how long do I have to stay in Spain to obtain citizenship?
I am currently starting my own business in my country and cannot stay for more than a year in Spain.

Thanks in advance!