Better off sticking with my current job or taking a related internship?

Okay, so I have been working at the same hardware store since I was 16. I am now 21 and have 5 years experience working there. In these 5 years I have been Employee of the Year twice, I have advanced several times to new positions and currently am a manager, I have attended a managers and leadership course through a college that my job paid for and received a certificate, and I have been sent to a technical school and received two separate small engine certifications to make repairs.

I am going to school for Industrial Technology and Mathematics, I am currently going into my senior year and plan to go to graduate school whenever I graduate either for Statistics and Data Science or for Electrical Engineering. Should I leave my current job (with great pay at $16 an hour plus bonuses) for a job/internships more related to my field or will my 40+ hours a week plus good grades while pursuing my degree speak more volume?

Also, I volunteer at my local soup kitchen every Tuesday and have over 100+ hours of volunteering.