We dated for 5 years. Knew each other a little for years before. Personally I say within a year you should be able to figure out if you're compatible, knowing if you're ready for marriage is a different thing. I think we knew pretty early on, but gotta let the initial love bug wear off a bit and get into some disagreements to really figure it out.
We'd likely would have gotten married earlier if I'd felt better about financial things, but eventually realized that would always be a concern. Looking back it was still good to take the time to get to know each other, but worrying about financials and details should not hold you back if you're willing to improve yourself and move onward and upward. Taking on life's challenges together is better.