Not to mention the gauge issue ! 9mm track scales out at 4’5”; too narrow really for ‘English’ trains never mind 5’3”. Although it’s still closer to Irish scale than OO Gauge and its scale 4.125 foot track
Seriously though, you need to weigh up what kind of railway you want. Having modelled in 2, 3, 4, 7 and 16mm scales, the general rule for indoor or shed layouts (garden railways change the rule) is that the smaller the scale, the more emphasis there is on a sweep of landscape with less emphasis on the rolling stock. It allows for longer trains, sweeping curves, and a real sense of place. As the scale gets bigger, the trains themselves dominate your field of view. The emphasis on detail gets greater, but it’s harder to find space for depth of scenic development. N gauge has got exceptionally sophisticated since I first encountered it 40 plus years ago. But OO gauge has a wider manufacturing base (in the U.K. outline area at least) and will always be easier to acquire. Nothing to stop you trying out a simple layout in N to see how it goes !