problem with startup please help me :(

Hi gays

I'm new at mac world and bad for me i had a big problem in my very first days

my problem is that my mac asked me to perform an update and i pressed update and restart i think it was an important one then the update proses went wrong somehow now when i press the power button the apple icon appear and immediately a the screen become more gray with some words wrote in it and tell me that i need to restart my computer

i don't now if you understood my problem but i put an attachment picture for the problem

by the way my device is macbook pro

i hope you gays help my i really started to hate my computer

 

no i didn't just the update and yes i could do that but isn't there any other way i don't want to lose my files by the why this is way i decided to get a mac because i got tired from the format and the constant losing of my files