56+ small tanks have no margin for error and are not in my opinion for beginners - EVERYTHING needs to be spot on including the stocking - conditions get bad really quickly in less than 55 Gallons depending on how many fish.
If you are on a budget for finance or for space then start small but then the number of fish you keep must start small but less than 20 gallons is really not practical for tropical, unfortunately many rush in and get far too many fish, often incompatible with one another, in too small a tank without thought for the proper filtration etc, before truly understanding the mechanics of tank maintenance, fish species and their compatibility, water conditions and such like. Small tanks are high maintenance and need far more frequent attention than large ones.
Plus as has been said a large number progress to a larger tank if they really get into it.
Why do I give this advice?
Because I started with a 3ft left by the previous owners of the house, moved up to a 4ft 215 litre and I found the limitations and problems of both. Since I travel a lot I got to know first hand how fast things go wrong or the pressure on you when things are wrong but you must still go away for days at a time - getting up at 3am to do water changes before leaving etc etc.