New job

Hi ladies so this is my first week at my new job at I can't be more happier. I still have two weeks left of training. So today I got to practice loading a truck with packages I'm a package handler at UPS. So today one of the higher ups cane to introduce himself to me an to check on how my progress was an he noticed I put a really heavy box on the very top instead of the bottom where it should've been my mistake I'm still learning. So he tells me you know I'm gonna talk to Dennis (another higher up) an see if he can put you in a different position putting small packages in bags on the conveyor belts. An now I'm all worried that I may loose my job because I made a mistake that could have injured me. I mean I wanna prove I can do my best just like the men can. I don't want no accommodations but I'm not gonna argue with a higher up I'm still a newbie. Should I be worried I may loose my job? Please help me. Any advice? I'm very worried.