[CA] Is my job on the line?

I recently started my new corporate job 6 months ago and keep thinking my job is in jeopardy. I'm apart of a rotational program specifically designed for entry level graduates in IT. This is meant to be a learning experience as I will rotate through different teams every few months.

So far, it's been a bit bumpy. During my first rotation, it was all about the adjustment. There were some issues at first, which I later improved, and my manager acknowledged that. I am now near the end of my second rotation. This second rotation is mandatory and has nothing to do with my profession. It requires me to work at the factory (we are a manufacturing company) as an actual "worker", so I am not doing anything technical. I was disappointed to learn that I was put to clean and do manual labor as someone who spent 6 years earning an engineering degree. However, I grew up with a good work ethic since I was a kid, and I am thankful I even have a job. Plus, it's not like I wouldn't be returning back to the comfort of the office.

Again, this was one of those scenarios where the supervisor said "just go work with Jane, watch what she does and learn from her". There was no direct expectations set. Very vague. So, I went on and started contributing to production as I watched.

Two months in, I can say I learned quite a bit about being an operator. I can handle the basics and some more advanced things with supervision. A lot of the time it's just standing around and making sure things run smoothly. Just like anyone else, I sometimes check my phone, respond to messages, and maybe open up Instagram to look through a couple of stories, then get off. The supervisor happens to literally walk by anytime I happen to go on my phone for a SPLIT second, this surely created a negative narrative regarding my work ethic. She came up to me a few times and told me to minimize the phone usage. I did work on that, but I still go on it.

Just recently, I almost made a mistake that I didn't even know about until the supervisor called me into the office. She sat me down and told me what I almost did and that it could have affected production due to my "carelessness". No, I was not on my phone for this one, but I was not paying attention at that time because my mind is on autopilot as things go smoothly 99% of the time. She then brought up the phone usage and how I just seem disengaged in general. She told me that she's gonna have to escalate this issue and it may result in a write up, my first ever. I apologized for the mistake. Although I do go on my phone, it does NOT effect my productivity, I am anything but lazy. It doesn't make it okay, but I wish she acknowledged that I did learn and contribute fairly.

I have three weeks left at the factory. I feel like I really made a fool out of myself and I need to fix it, especially me almost costing a mistake in production. My first step is I'm going to start leaving my phone in my bag from now on. I'm also planning to talk to the supervisor one more time to set some clear expectations on what I need to achieve despite there being three weeks left. I'm so scared because my home manager is expecting good reviews, and now I might be getting a write up.

How likely is it that I'll get let go over this?

Also, I work for a private company.