It sound dodgy, i would not bother tbh.
the chances of being sold off to a person who may well do some unknown evil upon you arehigh.
I worked as a cleaner and it started at 6-7am depending on the day. Also some workers may come in earlier we had a lady who started at 3-4am and the rest of us came in later. So 5am is reasonable enough. Even if your shifts would be from 7am some may start from 6 and she would need to have enough time to show you around and sort out the documents before she starts.
When I started I went in the next morning at 6am and started then. The only difference is the company was owned by my teachers partner which is how I got it in the first place. So I knew it was genuine.
The hours also changed because of different things. If someone went on a holiday or the place needed to be used earlier we would just be asked to come in earlier and we would. You decided to work there so you have to deal with early hours
She just texted me that I dont have to come in at 5, i can come at 6
..... what is wrong with people?