Applied for part time but when selecting pre-hire shift it now says full time?

Sorry this is a very basic question but I'm really lost and I really need the job

I got approved for a part time grocery fulfillment center job, it said no shifts available but later some came up, it said I needed to select these to have a pre-hire appointment. But now it lists the position as full time

Should I just wait until pre-hire appointment on Monday to talk to them? I have never worked for Amazon before so this is all new but im just really stressed out.

If it is a full time position would there likely be the option to switch to part time after a little bit?