All I can add is "go for it". Yes, it will take longer than you may think, but if you're new to an instrument, just take your time, practice regularly, and have fun.
As for the "lefty" / "righty" thing, try a few different instruments out, get what feels "right". You can only find out by trying some out. For your first instrument (and probably the first few after the first), buy from a shop, not online. They should help you choose the right bass for you. Don't spend too much either, you can get some really good basses for not much outlay.