Solo Oven employee

Only been with dominos for a short while, got hired at state minimum wage, I've explained to my boss that I want to try to go for management because insider hours are lacking but I was told I can't move up until I get better at ovens, what they're referring to is the fact that as a solo person on the three lane double conveyor ovens (sometimes the third row too) during a rush I can't keep up with everything, is it normal to be the only person on ovens during a rush at a busy store where the lanes are stuffed back to back with larges mediums, smalls, sides, pan pizzas and personal pans with no other person?

when I first started there was always two people on ovens now it just seems to fall to me and since I'm suffering at ovens my hours are at risk of being decreased.