I wasn't 100% sure about the timing, because we got married so soon. The result, avoidable issues that we eventually got thru.
Now, when my friends tell me they are getting married, I just ask them if they have any doubts. Because if you do - it doesn't make him a bad person, or mean he's not the one. It just means there's something in you that wants your attention.
You cannot predict the future of what a person might do. But you have to be rather certain of a man's character. That he has shown you consistent "fruit" or evidence through his actions and words of who he is. If you're at peace with that, you feel it's God will, you've prepared your self thru advice and counsel, and you love him....I'd say you should get married.