School and work?

So I am in my second year in university, and I was just offered a part time position that pays really well. That being said i am doing a full course load (15 hours a week) and the job wants to be work a minimum of 15 hours a week with 6 weeks of the 14 weeks in university being 20hours a those 6 weeks.....I am debating taking this job and would love to hear other people’s opinions? Do you think these 20 hours is to much as a student?

I get average grades but still want to do really well in school!