Alex...........you're getting great advice here! I would make it a small-ish layout and either portable or easy to disassemble. The reason is as you get into your late teens, all sorts of other "priorities" take over...........mainly called a significant other. But it should be easy from what I have read about your 'rents and grandparents being pro-trains. and of course all the skills you will learn and retain and rely on the rest of your life.
Just remember what Red Green says...............(this one you'll have to look up)!
