Congrats on the good grades !! I’d be curious as to WHAT you already have… a locomotive, box-cars ?? What type and time frame ?? Are you wanting to build a layout, and if so, big or little ?? What region of the country ??

One thing I would DEFINITELY recommend is a subscription to Model Railroader magazine http://www.trains.com/mrr/ They have great articles, plans, and advertisements.

Another thing I would do is SERIOUS thinking before starting a layout… lots of graph-paper… DRAW the layout you want first… it’s much easier and cheaper to correct things on paper than on a layout.

HO scale track is relatively inexpensive from the store, and rather cheap from eBay (I bought a ton of N-scale track there).

GOOD LUCK and Come back with more questions !!