Tiling a narrow room - Where to start?

Hi!
I have never tiled before, but I might want to try it in a very small room. The toilet is very narrow (80cm wide and about 2m long). There is marble in the hallway, which directly borders the old tiles in the toilet. I would like to lay 60x30 tiles, although most of them would need to be cut anyway. From back to front would be the easiest, but then I wouldn't know if I would end up exactly at the same height as the marble tiles.
Should I then start at the marble and only lay a side strip to the back and then from back to front, or how is this best done?
I also thought about trying such a leveling system (e.g., Proleveling tile leveling system), even though you probably have to work faster with it. What do you think?

As a pattern for laying, I was thinking of something like this:

whether I will arrive exactly at the same height as the marble tiles

How is the substrate, exactly? Is there a height offset?

Lay out the tiles beforehand, I wouldn't like the pattern. 10 cm - 60 cm - 10 cm is extremely unusual.

Consider (with a room depth of 2.00 m) whether you want the cut longitudinal side at the front or back.

Don't forget doors and wall partitions in the planning... nobody wants to see 5 cm leftover tiles ;)

Hello. With a width of 80 cm, 60 + 20 would work quite well. I wouldn't want to cut senselessly there. Regarding the heights, you can make markings on the walls. Regards.

For 80cm width, simply use 80-sized tiles. If you are working with a leveling system, that is no problem. Please use a tile lifter, at that size you can no longer lay them by hand.

I haven't removed the tiles yet because I wanted to first think about how and whether I will do it. The transition currently looks like this:

Consider (with 2.00 m room depth) whether you want the cut longitudinal side at the front or the back.

Well, I would rather want it at the back.

I wouldn't want to cut there without reason. You can make markings on the walls because of the heights. Regards.

What do you mean by "cutting without reason"? Even with markings, there can still be a few millimeters difference. Currently, the transition is at one height and that's how it should be again.

With 80 cm width, you simply take 80 cm tiles.

That would probably be simple because you don't have to cut anything, but I'm not sure if I like it that way.

I have never tiled before

Then keep your hands off. Right now it still looks nice (for now). ;)