Why is trying to play guitar so hard for me?

It sucks! Cause everytime in my guitar class I am unable to play along with the class when we practice/play songs, because (1.) it's just so hard to stretch my fingers to play cords-plus I kinda have small hands and it makes it a bit more difficult, and (2.) even sometimes when I manage to press down the string for cords it ends up not sounding how it should because most of the time my fingers are like touching/pressing others strings when I reach over with my fingers which then nulls the sound/ring of those strings...and like no matter how much I attempt to arc my finger(s) more and more that finger still nulls a string or two.... 😅-Sigh- I have a freaking playing test tomorrow and I don't think I'll do well at all because of this and just my ability/pace to switch between cords