Replacing oven light

I was told that in order to replace the oven light bulb in my Maytag oven I would simply need to unscrew the glass cover. I can see the old light bulb through the glass. A repair person I spoke with on the phone told me it might be really hard to unscrew and he was right. Even with a rubber gripper I couldn’t get it to budge. I don’t want to break the glass cover. I also don’t want to pay $100 for someone to come out and unscrew a cover when it costs just a few dollars to replace the light bulb. Because it seems to be so difficult, I’m wondering if it can be unscrewed. If so, what would be the best way?