Melissa, it just depends what length of a sock you want!! I am making two pairs of socks right now - one of them is about 1.5" of ribbing, followed by 5" of stockinette before starting the heel flap. It is not an extraordinarily long sock, by any stretch of the imagination, actually I wish I had made it longer. 8-9" total, including cuff, in my opinion is a good length for a sock. If you want an ankle sock, make it a lot shorter, it all depends on your preference. There is no wrong answer!!!
I'd hate for you to rip out what you've done, especially since it sounds like the makings of a perfectly fine sock, especially for your first! Keep at it and see how it comes out, then you'll know for next time what you liked and didn't like about it.