HI Sarah
The layout you have shown is a floor plan layout. It will be great fun to run and has lots of sidings for rolling stock and shunting activity if that is what you like doing...and no reverse loop.
What it does not have is much room for garden, so it would do better on the patio (or sitting room or lawn) but if you start adding plants and buildings you will probably begin to find it has limitations.
I stated on the patio with something just like this and enjoyed it but then wanted to make it bigger. 28 years and 4 layouts later I now have about 30 full trains and 40 loco's all chipped and 350 meters of track running in and out of a big custom train shed. The whole train area is landscaped and on several levels. I can now run 5 trains on separate circuits or with help 9 trains, and I have not finished yet.
BUT I still have the very first bits of track I ever bought and they are in the layout somewhere.
If you want to build a landscaped garden railway then what you propose wont leave much room for the plants, but even if is just what you want now, at some stage you will want to take it up and change it or expand it or even get bored with trains and sell it. As someone has already said, set track it great for this and a layout like the one you propose is small enough to put up temporarily, use, find out its limitations and then modify. You can go on doing that easily until you start hard landscaping, then it all gets a bit more difficult.
I am on my third landscaped layout and each one has incorporated the lessons I learnt the previous time. Whatever you do this time will not be perfect and some of the fun for most of us is making changes. How easy you make this for yourself is up to you, but I personally would not commit too much time and effort to shifting lots of dirt till I have a better idea of exactly what I enjoy most about garden railways....unless of course for you the dirt moving is part of the fun (as it is for me), in which case your layout will never be finished anyway so don't worry.