if your feet are bigger than an 11 you need a “wide” board. otherwise you’re fine.
as jaeger said don’t go to stiff. it will control you. If you’re 5’8" i’d say more like 149~151cm. again i agree, rent first to make sure you like it. thats what i tell everyone before buying a board (although I’ve never met anyone who didn’t like it, besides that one token girl who bought everything brand new, all white snowsuit, and didn’t like snowboarding cause it made her gear dirty when she fell).
then try and buy used. i work at a shop and get new shit every year, and unfortunately the past few years I’ve hurt myself either skateboarding or playing hockey, so I barely ride my shit. and sell it dirt cheap
there are many like me.
find one.