working with stone is damn hard, especially with smaller pieces of it. know thy stone, certain kinds dont like getting cut and break, some kinds look fugly when cut, and some are just too hard to cut with hobby tools. and don't forget that there'll be dust. lots of it. everywhere. so get a dust sucker (or whatever you guys call it) and always wear a mask. also use glue instead of mortar, you'll thank me.
i'd say go ahead, cut some blocks and try building an arch first. if you are not bored off ass after the fifth block, you're good to go.