wdid scared to go to a new job

So, I am a 20-year-old woman, and I graduated as an electrician from vocational school six months ago.
My time in school was quite difficult because my teacher was very mean to me and did not like having female students, since he believed it was “for men.”

My teacher constantly discouraged me and told me that I wasn’t capable, and eventually I started to believe it. As a result, I became afraid to do any electrical work at all. In the end, I graduated later with the approval of a different teacher.

However, I still feel like I am not competent enough. Today, I received a phone call from a large electrical company asking if I would like to start working there next week. Apparently, a friend of mine had recommended me, although she works for a different company.

I have been avoiding electrician jobs because of my lack of confidence, and I often feel very inexperienced, stupid, and inadequate. However, I was honest with the employer about my fears. I told him that I struggle with insecurity and nervousness when it comes to working. He said he understood and assured me that you learn by doing.

I am extremely nervous. What if I don’t know how to do the work? What if I am not qualified enough? Have other people, especially electricians, experienced similar fears when starting their first job?

WDID how to get rid of being scared? Is it unprofessional to ask for help with simple work that I should know to do on my own?