I finished a bachelor degree
bachelor's degree
then , I've been working as a spanish teacher
no space before comma
I did not know almost nothing about networking
double negative; your statement as written means you knew more than nothing
If you want to call me a liar, is up to you
missing pronoun
maybe you are the one that have a degree in beautician
subject is singular, your verb is plural; beautician is a noun
Grantham University is an excellent university, is up to you
missing pronoun
If your post is an example of how Grantham University trains its students in writing skills, you're going to have problems moving up the corporate ladder.